# Patent

## Title
Methods, reagents and cells for biosynthesizing compounds

## Abstract

This document describes biochemical pathways for producing 2(E)-heptenedioyl-CoA methyl ester from precursors such as 2-oxo-glutarate, acetyl-CoA, or succinyl-CoA using one or more of a fatty acid O-methyltransferase, a thioesterase, a CoA-transferase, a CoA ligase, as well as recombinant hosts expressing one or more of such enzymes. 2(E)-heptenedioyl-CoA methyl ester can be enzymatically converted to pimeloyl-CoA using a trans-2-enoyl-CoA reductase, and a methylesterase. Pimeloyl-CoA can be enzymatically converted to pimelic acid, 7-aminoheptanoate, 7-hydroxyheptanoate, heptamethylenediamine, or 1,7-heptanediol.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Application Nos. 62/012,674 and 62/012,735, both of which were filed on Jun. 16, 2014, the disclosures of which are incorporated by reference herein in their entireties.


TECHNICAL FIELD
This invention relates to methods of shielding a carbon chain aliphatic backbone, functionalized with terminal carboxyl groups, in a recombinant host using a polypeptide having the activity of a fatty acid O-methyltransferase. This invention also relates to methods for biosynthesizing heptenedioyl-CoA methyl ester in a host using one or more of (i) a polypeptide having fatty acid O-methyltransferase activity (ii) a polypeptide having thioesterase activity or CoA-transferase activity, or (iii) a polypeptide having CoA ligase activity, and to recombinant host cells expressing one or more such enzymes. In addition, this invention also relates to methods for enzymatically converting hept-2-enedioyl-CoA methyl ester to pimeloyl-CoA using a polypeptide having trans-enoyl-CoA reductase activity and/or a polypeptide having pimeloyl-[acp] methyl ester esterase activity, and enzymatically converting pimeloyl-CoA to one or more of pimelic acid, 7-aminoheptanoic acid, heptamethylenediamine, 7-hydroxyheptanoic acid, and 1,7-heptanediol (hereafter “C7 building blocks”), and recombinant hosts that produce such C7 building blocks.
BACKGROUND
Nylons are polyamides which are sometimes synthesized by the condensation polymerisation of a diamine with a dicarboxylic acid. Similarly, nylons may be produced by the condensation polymerisation of lactams. A ubiquitous nylon is Nylon 6,6, which is produced by reaction of hexamethylenediamine (HMD) and adipic acid. Nylon 6 is produced by a ring opening polymerisation of caprolactam (Anton & Baird, Polyamides Fibers, Encyclopedia of Polymer Science and Technology, 2001).
Nylon 7 and Nylon 7,7 represent novel polyamides with value-added characteristics compared to Nylon 6 and Nylon 6,6. Nylon 7 is produced by polymerisation of 7-aminoheptanoic acid, whereas Nylon 7,7 is produced by condensation polymerisation of pimelic acid and heptamethylenediamine. No economically viable petrochemical routes exist to producing the monomers for Nylon 7 and Nylon 7,7.
Given no economically viable petrochemical monomer feedstocks, biotechnology offers an alternative approach via biocatalysis. Biocatalysis is the use of biological catalysts, such as enzymes, to perform biochemical transformations of organic compounds.
Both bioderived feedstocks and petrochemical feedstocks are viable starting materials for the biocatalysis processes.
Accordingly, against this background, it is clear that there is a need for methods for producing pimelic acid, 7-aminoheptanoic acid, heptamethylenediamine, 7-hydroxyheptanoic acid and 1,7-heptanediol (hereafter “C7 building blocks”) wherein the methods are biocatalyst-based.
However, no wild-type prokaryote or eukaryote naturally overproduces or excretes C7 building blocks to the extracellular environment. Nevertheless, the metabolism of pimelic acid has been reported.
The dicarboxylic acid, pimelic acid, is converted efficiently as a carbon source by a number of bacteria and yeasts via β-oxidation into central metabolites. β-oxidation of CoEnzyme A (CoA) activated pimelate to CoA-activated 3-oxopimelate facilitates further catabolism via, for example, pathways associated with aromatic substrate degradation. The catabolism of 3-oxopimeloyl-CoA to acetyl-CoA and glutaryl-CoA by several bacteria has been characterized comprehensively (Harwood and Parales, Annual Review of Microbiology, 1996, 50, 553-590).
The optimality principle states that microorganisms regulate their biochemical networks to support maximum biomass growth. Beyond the need to express heterologous pathways in a host organism, directing carbon flux towards C7 building blocks that serve as carbon sources rather than to biomass growth constituents, contradicts the optimality principle. For example, transferring the 1-butanol pathway from Clostridium species into other production strains has often fallen short by an order of magnitude compared to the production performance of native producers (Shen et al., Appl. Environ. Microbiol., 2011, 77(9), 2905-2915).
The efficient synthesis of the seven carbon aliphatic backbone precursor is a key consideration in synthesizing C7 building blocks prior to forming terminal functional groups, such as carboxyl, amine or hydroxyl groups, on the C7 aliphatic backbone.
SUMMARY
This document is based at least in part on the discovery that it is possible to construct biochemical pathways via hept-2-enedioyl-CoA (also referred to as 2-heptenedioyl-CoA)methyl ester for producing a seven carbon chain aliphatic backbone precursor such as pimeloyl-CoA, in which one or two functional groups, i.e., carboxyl, amine, or hydroxyl, can be formed, leading to the synthesis of one or more of pimelic acid, 7-aminoheptanoate, 7-hydroxyheptanoate, heptamethylenediamine, and 1,7-heptanediol (hereafter “C7 building blocks). Pimelic acid and pimelate, 7-hydroxyheptanoic acid and 7-hydroxyheptanoate, and 7-aminoheptanoic and 7-aminoheptanoate are used interchangeably herein to refer to the compound in any of its neutral or ionized forms, including any salt forms thereof. It is understood by those skilled in the art that the specific form will depend on pH. These pathways, metabolic engineering and cultivation strategies described herein rely on producing 2(E)-heptenedioate methyl ester from 2(E)-heptenedioate using, for example, a fatty acid O-methyltransferase and producing 2(E)-heptenedioyl-CoA methyl ester from 2(E)-heptenedioate methyl ester using, for example, a CoA ligase. Pimeloyl-CoA can be produced from 2(E)-heptenedioyl-CoA methyl ester using, for example, a trans-2-enoyl-CoA reductase and a pimelyl-[acp] methyl ester esterase. 2(E)-heptenedioate can be produced, for example, from 2-oxoglutarate, acetyl-CoA or succinate semialdehyde as shown in FIGS. 1, 2, and 3, respectively.
In the face of the optimality principle, it surprisingly has been discovered that appropriate non-natural pathways, feedstocks, host microorganisms, attenuation strategies to the host's biochemical network and cultivation strategies may be combined to efficiently produce one or more C7 building blocks.
In some embodiments, a terminal carboxyl group can be enzymatically formed using a thioesterase, an aldehyde dehydrogenase, a 7-oxoheptanoate dehydrogenase, a 6-oxohexanoate dehydrogenase, a 5-oxopentanoate dehydrogenase, a reversible CoA-ligase (e.g., a reversible succinyl-CoA-ligase), or a CoA-transferase (e.g., a glutaconate CoA-transferase). See, FIG. 4.
In some embodiments, a terminal amine group can be enzymatically formed using a ω-transaminase or a deacetylase. See, FIGS. 5 and 6.
In some embodiments, a terminal hydroxyl group can be enzymatically formed using a 4-hydroxybutyrate dehydrogenase, 5-hydroxypentanoate dehydrogenase, a 6-hydroxyhexanoate dehydrogenase, or an alcohol dehydrogenase. See, FIGS. 7 and 8.
The two terminal functional groups can be the same (e.g., amine or hydroxyl) or can be different (e.g., a terminal amine and a terminal carboxyl group; or a terminal hydroxyl group and a terminal carboxyl group).
Any of the methods can be performed in a recombinant host by fermentation. The host can be subjected to a cultivation strategy under anaerobic, micro-aerobic or mixed oxygen/denitrification cultivation conditions. The host can be cultured under conditions of nutrient limitation. The host can be retained using a ceramic membrane to maintain a high cell density during fermentation. The final electron acceptor can be an alternative to oxygen such as nitrates.
In any of the methods, the host's tolerance to high concentrations of a C7 building block can be improved through continuous cultivation in a selective environment.
The principal carbon source fed to the fermentation can derive from biological or non-biological feedstocks. In some embodiments, the biological feedstock is, includes, or derives from, monosaccharides, disaccharides, lignocellulose, hemicellulose, cellulose, lignin, levulinic acid and formic acid, triglycerides, glycerol, fatty acids, agricultural waste, condensed distillers' solubles, or municipal waste.
In some embodiments, the non-biological feedstock is or derives from natural gas, syngas, CO2/H2, methanol, ethanol, benzoate, non-volatile residue (NVR) or a caustic wash waste stream from cyclohexane oxidation processes, or a terephthalic acid/isophthalic acid mixture waste stream.
This document features a recombinant host that includes at least one exogenous nucleic acid encoding (i) a fatty acid O-methyltransferase; and (ii) a thioesterase or CoA-transferase, the host producing 2(E)-heptenedioate methyl ester. The host can further include an exogenous CoA ligase, the host further producing 2(E)-heptenedioyl-CoA methyl ester. In some embodiments, the host can further include an exogenous trans-2-enoyl-CoA reductase and/or an exogenous pimeloyl-[acp] methyl ester methylesterase, and produce pimeloyl-CoA.
This document also features a recombinant host that includes at least one exogenous nucleic acid encoding (i) a fatty acid O-methyltransferase; and (ii) a CoA ligase, the host producing 2(E)-heptenedioyl-CoA methyl ester. Such a host further can include an exogenous thioesterase or CoA-transferase. In some embodiments, the host can further include an exogenous trans-2-enoyl-CoA reductase and/or an exogenous pimeloyl-[acp] methyl ester methylesterase, and produce pimeloyl-CoA.
A recombinant host producing pimeloyl-CoA further can include at least one exogenous nucleic acid encoding one or more of a thioesterase, an aldehyde dehydrogenase, a 7-oxoheptanoate dehydrogenase, a 6-oxohexanoate dehydrogenase, a 5-oxopentanoate dehydrogenase, a CoA-transferase, a reversible CoA-ligase (e.g., a reversible succinyl-CoA-ligase), an acetylating aldehyde dehydrogenase, or a carboxylate reductase, the host producing pimelic acid or pimelate semialdehyde. In any of the recombinant hosts expressing a carboxylate reductase, a phosphopantetheinyl transferase also can be expressed to enhance the activity of the carboxylate reductase.
A recombinant host producing pimelate semialdehyde further can include at least one exogenous nucleic acid encoding a ω-transaminase, and further produce 7-aminoheptanoate.
A recombinant host producing pimelate semialdehyde further can include at least one exogenous nucleic acid encoding a 4-hydroxybutyrate dehydrogenase, a 5-hydroxypentanoate dehydrogenase or a 6-hydroxyhexanoate dehydrogenase, the host further producing 7-hydroxyheptanoic acid.
A recombinant host producing pimelate semialdehyde, 7-aminoheptanoate, or 7-hydroxyheptanoic acid further can include a carboxylate reductase, a ω-transaminase, a deacetylase, an N-acetyl transferase, or an alcohol dehydrogenase, the host further producing heptamethylenediamine.
A recombinant host producing 7-hydroxyheptanoic acid further can include at least one exogenous nucleic acid encoding a carboxylate reductase or an alcohol dehydrogenase, the host further producing 1,7-heptanediol.
The recombinant host can be a prokaryote, e.g., from the genus Escherichia such as Escherichia coli; from the genus Clostridia such as Clostridium ljungdahlii, Clostridium autoethanogemum or Clostridium kluyveri; from the genus Corynebacteria such as Corynebacterium glutamicum; from the genus Cupriavidus such as Cupriavidus necator or Cupriavidus metallidurans; from the genus Pseudomonas such as Pseudomonas fluorescens, Pseudomonas putida or Pseudomonas oleavorans; from the genus Delftia acidovorans, from the genus Bacillus such as Bacillus subtillis; from the genes Lactobacillus such as Lactobacillus delbrueckii; from the genus Lactococcus such as Lactococcus lactis or from the genus Rhodococcus such as Rhodococcus equi. 
The recombinant host can be an eukaryote, e.g., a eukaryote from the genus Aspergillus such as Aspergillus niger; from the genus Saccharomyces such as Saccharomyces cerevisiae; from the genus Pichia such as Pichia pastoris; from the genus Yarrowia such as Yarrowia lipolytica, from the genus Issatchenkia such as Issathenkia orientalis, from the genus Debaryomyces such as Debaryomyces hansenii, from the genus Arxula such as Arxula adenoinivorans, or from the genus Kluyveromyces such as Kluyveromyces lactis. 
Any of the recombinant hosts described herein further can include one or more of the following attenuated enzymes: polyhydroxyalkanoate synthase, an acetyl-CoA thioesterase, an acetyl-CoA specific β-ketothiolase, a phosphotransacetylase forming acetate, an acetate kinase, a lactate dehydrogenase, a menaquinol-fumarate oxidoreductase, an alcohol dehydrogenase forming ethanol, a triose phosphate isomerase, a pyruvate decarboxylase, a glucose-6-phosphate isomerase, a transhydrogenase dissipating the NADPH imbalance, an glutamate dehydrogenase dissipating the NADPH imbalance, a NADH/NADPH-utilizing glutamate dehydrogenase, a pimeloyl-CoA dehydrogenase; an acyl-CoA dehydrogenase accepting C7 building blocks and central precursors as substrates; a glutaryl-CoA dehydrogenase; or a pimeloyl-CoA synthetase.
Any of the recombinant hosts described herein further can overexpress one or more genes encoding: an acetyl-CoA synthetase, a 6-phosphogluconate dehydrogenase; a transketolase; a puridine nucleotide transhydrogenase; a formate dehydrogenase; a glyceraldehyde-3P-dehydrogenase; a malic enzyme; a glucose-6-phosphate dehydrogenase; a fructose 1,6 diphosphatase; a L-alanine dehydrogenase; a PEP carboxylase, a pyruvate carboxylase, PEP carboxykinase, PEP synthase, a L-glutamate dehydrogenase specific to the NADPH used to generate the imbalance; a methanol dehydrogenase, a formaldehyde dehydrogenase, a lysine transporter; a dicarboxylate transporter; an S-adenosylmethionine synthetase, a 3-phosphoglycerate dehydrogenase, a 3-phosphoserine aminotransferase, a phosphoserine phosphatase, and/or a multidrug transporter.
The reactions of the pathways described herein can be performed in one or more cell (e.g., host cell) strains (a) naturally expressing one or more relevant enzymes, (b) genetically engineered to express one or more relevant enzymes, or (c) naturally expressing one or more relevant enzymes and genetically engineered to express one or more relevant enzymes. Alternatively, relevant enzymes can be extracted from any of the above types of host cells and used in a purified or semi-purified form. Extracted enzymes can optionally be immobilized to a solid substrate such as the floors and/or walls of appropriate reaction vessels. Moreover, such extracts include lysates (e.g., cell lysates) that can be used as sources of relevant enzymes. In the methods provided by the document, all the steps can be performed in cells (e.g., host cells), all the steps can be performed using extracted enzymes, or some of the steps can be performed in cells and others can be performed using extracted enzymes.
Many of the enzymes described herein catalyze reversible reactions, and the reaction of interest may be the reverse of the described reaction. The schematic pathways shown in FIGS. 1 to 8 illustrate the reaction of interest for each of the intermediates.
In one aspect, this document features a method for producing a bioderived seven carbon compound. The method for producing a bioderived seven carbon compound can include culturing or growing a recombinant host as described herein under conditions and for a sufficient period of time to produce the bioderived seven carbon compound, wherein, optionally, the bioderived seven carbon compound is selected from the group consisting of pimelic acid, 7-aminoheptanoate, 7-hydroxyheptanoate, heptamethylenediamine, 1,7-heptanediol, and combinations thereof.
In one aspect, this document features composition comprising a bioderived seven carbon compound as described herein and a compound other than the bioderived seven carbon compound, wherein the bioderived seven carbon compound is selected from the group consisting of pimelic acid, 7-aminoheptanoate, 7-hydroxyheptanoate, heptamethylenediamine, 1,7-heptanediol, and combinations thereof. For example, the bioderived seven carbon compound is a cellular portion of a host cell or an organism.
This document also features a biobased polymer comprising the bioderived pimelic acid, 7-aminoheptanoate, 7-hydroxyheptanoate, heptamethylenediamine, 1,7-heptanediol, and combinations thereof.
This document also features a biobased resin comprising the bioderived pimelic acid, 7-aminoheptanoate, 7-hydroxyheptanoate, heptamethylenediamine, 1,7-heptanediol, and combinations thereof, as well as a molded product obtained by molding a biobased resin.
In another aspect, this document features a process for producing a biobased polymer that includes chemically reacting the bioderived pimelic acid, 7-aminoheptanoate, 7-hydroxyheptanoate, heptamethylenediamine, or 1,7-heptanediol, with itself or another compound in a polymer producing reaction.
In another aspect, this document features a process for producing a biobased resin that includes chemically reacting the bioderived pimelic acid, 7-aminoheptanoate, 7-hydroxyheptanoate, heptamethylenediamine, or 1,7-heptanediol, with itself or another compound in a resin producing reaction.
Also, described herein is a biochemical network comprising a polypeptide having fatty acid O-methyltransferase activity, wherein the polypeptide having fatty acid O-methyltransferase activity enzymatically converts 2(E) heptenedioic acid to 2(E) heptenedioate methyl ester. The biochemical network can further include a polypeptide having CoA ligase activity, wherein the polypeptide having CoA ligase activity enzymatically converts 2(E) heptenedioate methyl ester to 2(E) heptenedioyl-CoA methyl ester. The biochemical network can further include a polypeptide having trans-2-enoyl-CoA reductase activity, wherein the polypeptide having trans-2-enoyl-CoA reductase activity enzymatically converts 2(E) heptenedioyl-CoA methyl ester to pimeloyl-CoA methyl ester. The biochemical network can further include a polypeptide having pimelyl-[acp] methyl ester esterase activity, wherein the polypeptide having pimelyl-[acp] methyl ester esterase activity enzymatically converts pimeloyl-CoA methyl ester to pimeloyl-CoA.
The biochemical network can further include one or more polypeptides having thioesterase, reversible CoA-ligase, glutaconate CoA-transferase, ω-transaminase, 6-hydroxyhexanoate dehydrogenase, 5-hydroxypentanoate dehydrogenase, 4-hydroxybutyrate dehydrogenase, alcohol dehydrogenase, carboxylate reductase, or alcohol dehydrogenase activity, wherein the one or more polypeptides having thioesterase, reversible CoA-ligase, glutaconate CoA-transferase, ω-transaminase, 6-hydroxyhexanoate dehydrogenase, 5-hydroxypentanoate dehydrogenase, 4-hydroxybutyrate dehydrogenase, alcohol dehydrogenase, carboxylate reductase, or alcohol dehydrogenase activity enzymatically convert pimeloyl-CoA to a product selected from the group consisting of pimelic acid, 7-aminoheptanoate, 7-hydroxyheptanoate, heptamethylenediamine, and 1,7-heptanediol.
Also, described herein is a means for obtaining 2(E)-heptenedioate methyl ester, 2-heptenedioyl-CoA methyl ester, pimelic acid, 7-aminoheptanoate, 7-hydroxyheptanoate, heptamethylenediamine, and 1,7-heptanediol using one or more polypeptides having thioesterase, reversible CoA-ligase, glutaconate CoA-transferase, ω-transaminase, 6-hydroxyhexanoate dehydrogenase, 5-hydroxypentanoate dehydrogenase, 4-hydroxybutyrate dehydrogenase, alcohol dehydrogenase, carboxylate reductase or alcohol dehydrogenase activity.
In another aspect, this document features a composition comprising one or more polypeptides having fatty acid O-methyltransferase, thioesterase, reversible CoA-ligase, glutaconate CoA-transferase, ω-transaminase, 6-hydroxyhexanoate dehydrogenase, 5-hydroxypentanoate dehydrogenase, 4-hydroxybutyrate dehydrogenase, alcohol dehydrogenase, carboxylate reductase, or alcohol dehydrogenase activity and at least one of 2(E)-heptenedioate methyl ester, 2-heptenedioyl-CoA methyl ester, pimelic acid, 7-aminoheptanoate, 7-hydroxyheptanoate, heptamethylenediamine, and 1,7-heptanediol. The composition can be cellular.
One of skill in the art understands that compounds containing carboxylic acid groups (including, but not limited to, organic monoacids, hydroxyacids, aminoacids, and dicarboxylic acids) are formed or converted to their ionic salt form when an acidic proton present in the parent compound either is replaced by a metal ion, e.g., an alkali metal ion, an alkaline earth ion, or an aluminum ion; or coordinates with an organic base. Acceptable organic bases include, but are not limited to, ethanolamine, diethanolamine, triethanolamine, tromethamine, N-methylglucamine, and the like. Acceptable inorganic bases include, but are not limited to, aluminum hydroxide, calcium hydroxide, potassium hydroxide, sodium carbonate, sodium hydroxide, and the like. A salt of the present invention is isolated as a salt or converted to the free acid by reducing the pH to below the pKa, through addition of acid or treatment with an acidic ion exchange resin.
One of skill in the art understands that compounds containing amine groups (including, but not limited to, organic amines, aminoacids, and diamines) are formed or converted to their ionic salt form, for example, by addition of an acidic proton to the amine to form the ammonium salt, formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like; or formed with organic acids including, but not limited to, acetic acid, propionic acid, hexanoic acid, cyclopentanepropionic acid, glycolic acid, pyruvic acid, lactic acid, malonic acid, succinic acid, malic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, 3-(4-hydroxybenzoyl)benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, 1,2-ethanedisulfonic acid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid, 2-naphthalenesulfonic acid, 4-methylbicyclo-[2.2.2]oct-2-ene-1-carboxylic acid, glucoheptonic acid, 4,4′-methylenebis-(3-hydroxy-2-ene-1-carboxylic acid), 3-phenylpropionic acid, trimethylacetic acid, tertiary butylacetic acid, lauryl sulfuric acid, gluconic acid, glutamic acid, hydroxynaphthoic acid, salicylic acid, stearic acid, muconic acid, and the like. Acceptable inorganic bases include, but are not limited to, aluminum hydroxide, calcium hydroxide, potassium hydroxide, sodium carbonate, sodium hydroxide, and the like. A salt of the present invention is isolated as a salt or converted to the free amine by raising the pH to above the pKb through addition of base or treatment with a basic ion exchange resin.
One of skill in the art understands that compounds containing both amine groups and carboxylic acid groups (including, but not limited to, aminoacids) are formed or converted to their ionic salt form by either 1) acid addition salts, formed with inorganic acids including, but not limited to, hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like; or formed with organic acids including, but not limited to, acetic acid, propionic acid, hexanoic acid, cyclopentanepropionic acid, glycolic acid, pyruvic acid, lactic acid, malonic acid, succinic acid, malic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, 3-(4-hydroxybenzoyl)benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, 1,2-ethanedisulfonic acid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid, 2-naphthalenesulfonic acid, 4-methylbicyclo-[2.2.2]oct-2-ene-1-carboxylic acid, glucoheptonic acid, 4,4′-methylenebis-(3-hydroxy-2-ene-1-carboxylic acid), 3-phenylpropionic acid, trimethylacetic acid, tertiary butylacetic acid, lauryl sulfuric acid, gluconic acid, glutamic acid, hydroxynaphthoic acid, salicylic acid, stearic acid, muconic acid, and the like. Acceptable inorganic bases include, but are not limited to, aluminum hydroxide, calcium hydroxide, potassium hydroxide, sodium carbonate, sodium hydroxide, and the like, or 2) when an acidic proton present in the parent compound either is replaced by a metal ion, e.g., an alkali metal ion, an alkaline earth ion, or an aluminum ion; or coordinates with an organic base. Acceptable organic bases include, but are not limited to, ethanolamine, diethanolamine, triethanolamine, tromethamine, N-methylglucamine, and the like. Acceptable inorganic bases include, but are not limited to, aluminum hydroxide, calcium hydroxide, potassium hydroxide, sodium carbonate, sodium hydroxide, and the like. A salt can of the present invention is isolated as a salt or converted to the free acid by reducing the pH to below the pKa through addition of acid or treatment with an acidic ion exchange resin.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although methods and materials similar or equivalent to those described herein can be used to practice the invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein including GenBank and NCBI submissions with accession numbers are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and the drawings, and from the claims. The word “comprising” in the claims may be replaced by “consisting essentially of” or with “consisting of,” according to standard practice in patent law.



DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic of exemplary biochemical pathways leading to pimeloyl-CoA from 2-oxo-glutarate or acetyl-CoA, via a hept-2-enedioyl-CoA methyl ester.
FIG. 2 is a schematic of an exemplary biochemical pathway leading to pimeloyl-CoA from 2-oxo-glutarate via a hept-2-enedioyl-CoA methyl ester.
FIG. 3 is a schematic of exemplary biochemical pathways leading to pimeloyl-CoA from succinyl-CoA or 2-oxo-glutarate via a hept-2-enedioyl-CoA methyl ester.
FIG. 4 is schematic of exemplary biochemical pathways leading to pimelic acid using pimeloyl-CoA as a central precursor.
FIG. 5 is a schematic of exemplary biochemical pathways leading to 7-aminoheptanoate using pimeloyl-CoA or pimelate as a central precursor.
FIG. 6 is a schematic of exemplary biochemical pathways leading to heptamethylenediamine using 7-aminoheptanoate, 7-hydroxyheptanoate, or pimelate semialdehyde as a central precursor.
FIG. 7 is a schematic of exemplary biochemical pathways leading to 7-hydroxyheptanoate using pimelate, pimeloyl-CoA or pimelate semialdehyde as a central precursor.
FIG. 8 is a schematic of an exemplary biochemical pathway leading to 1,7-heptanediol using 7-hydroxyheptanoate as a central precursor.
FIGS. 9A-9Q contains the amino acid sequences of a Mycobacterium marimum fatty acid O-methyltransferase (GenBank Accession No. ACC41782.1; SEQ ID NO: 1), a Mycobacterium smegmatis str. MC2 fatty acid O-methyltransferase (GenBank Accession No. ABK73223.1; SEQ ID NO: 2), a Pseudomonas putida fatty acid O-methyltransferase (GenBank Accession No. CAA39234.1; SEQ ID NO: 3), a Lactobacillus brevis acyl-[acp] thioesterase (GenBank Accession No. ABJ63754.1, SEQ ID NO: 4), a Lactobacillus plantarum acyl-[acp] thioesterase (GenBank Accession No. CCC78182.1, SEQ ID NO: 5), an Escherichia coli pimelyl-[acp] methyl ester esterase (see GenBank Accession No. AAC76437.1, SEQ ID NO: 6), a Mycobacterium marinum carboxylate reductase (See Genbank Accession No. ACC40567.1, SEQ ID NO: 7), a Mycobacterium smegmatis carboxylate reductase (See Genbank Accession No. ABK71854.1, SEQ ID NO: 8), a Segniliparus rugosus carboxylate reductase (See Genbank Accession No. EFV11917.1, SEQ ID NO: 9), a Mycobacterium smegmatis carboxylate reductase (See Genbank Accession No. ABK75684.1, SEQ ID NO: 10), a Mycobacterium massiliense carboxylate reductase (See Genbank Accession No. EIV1143.1, SEQ ID NO: 11), a Segniliparus rotundus carboxylate reductase (See Genbank Accession No. ADG98140.1, SEQ ID NO: 12), a Chromobacterium violaceum ω-transaminase (See Genbank Accession No. AAQ59697.1, SEQ ID NO: 13), a Pseudomonas aeruginosa ω-transaminase (See Genbank Accession No. AAG08191.1, SEQ ID NO: 14), a Pseudomonas syringae ω-transaminase (See Genbank Accession No. AAY39893.1, SEQ ID NO: 15), a Rhodobacter sphaeroides ω-transaminase (see Genbank Accession No. ABA81135.1, SEQ ID NO: 16), an Escherichia coli ω-transaminase (see Genbank Accession No. AAA57874.1, SEQ ID NO: 17), a Vibrio fluvialis ω(-transaminase (see Genbank Accession No. AEA39183.1, SEQ ID NO: 18), a Bacillus subtilis phosphopantetheinyl transferase (see Genbank Accession No. CAA44858.1, SEQ ID NO: 19), a Nocardia sp. NRRL 5646 phosphopantetheinyl transferase (see Genbank Accession No. ABI83656.1, SEQ ID NO: 20), an Escherichia coli thioesterase encoded by tesB (See GenBank Accession No. AAA24665.1, SEQ ID NO: 21), an Escherichia coli long-chain-fatty-acid-CoA ligase (Genbank Accession No. CAA50321.1, SEQ ID NO: 22), a Cupriavidus necator long-chain-fatty-acid-CoA ligase (Genbank Accession No. CAJ95550.1, SEQ ID NO: 23), an Acidaminococcus fermentans glutaconate CoA-transferase (see, e.g., Genbank Accession No. CAA57199.1 (GctA) and CAA57200.1 (GctB), SEQ ID NOs: 24 and 25, respectively), a Treponema denticola enoyl-CoA reductase (see, e.g., Genbank Accession No. AAS11092.1, SEQ ID NO: 26), an Euglena gracilis enoyl-CoA reductase (see, e.g., Genbank Accession No. AAW66853.1, SEQ ID NO: 27), a Pseudomonas reinekei MT1 β-ketothiolase (see, e.g., Genbank Accession No. ACZ63623.1, SEQ ID NO: 28), a Pseudomonas putida β-ketothiolase (see, e.g., Genbank Accession No. AAA85138.1, SEQ ID NO: 29), a Burkholderia xenovorans β-ketothiolase (see, e.g., Genbank Accession No. ABE33819.1, SEQ ID NO: 30), an Arthrobacter sp. β-ketothiolase (see, e.g., Genbank Accession No. ABK03524.1, SEQ ID NO: 31), a Burkholderia xenovorans β-ketothiolase (see, e.g., Genbank Accession No. ABE36495.1, SEQ ID NO: 32), a Geobacillus kaustophilus β-ketothiolase (see, e.g., Genbank Accession No. BAD75605.1, SEQ ID NO: 33), a Gordonia bronchialis β-kelothiolase (see, e.g., Genbank Accession ACY20886.1, SEQ ID NO: 34), a Citrobacter freundii β-ketothiolase (see, e.g., Genbank Accession KFB98168.1, SEQ ID NO: 35), a Burkholderia sp. β-ketothiolase (see, e.g., Genbank Accession ADG18081.1, SEQ ID NO: 36), a Beijerinckia indica β-ketothiolase (see, e.g., Genbank Accession ACB95386.1, SEQ ID NO: 37), an Arthrobacter arilaitensis β-ketothiolase (see, e.g., Genbank Accession CBT74677.1, SEQ ID NO: 38), a Cupriavidus necator β-ketothiolase (see, e.g., Genbank Accession AAC38322.1, SEQ ID NO: 39), and an Escherichia coli β-ketothiolase (see, e.g., Genbank Accession AAC74479.1, SEQ ID NO: 40).
FIG. 10 is a bar graph of the relative absorbance at 412 nm after 20 minutes of released CoA as a measure of the activity of a thioesterase for converting pimeloyl-CoA to pimelate relative to the empty vector control.
FIG. 11 is a bar graph summarizing the change in absorbance at 340 nm after 20 minutes, which is a measure of the consumption of NADPH and activity of carboxylate reductases relative to the enzyme only controls (no substrate).
FIG. 12 is a bar graph of the change in absorbance at 340 nm after 20 minutes, which is a measure of the consumption of NADPH and the activity of carboxylate reductases for converting pimelate to pimelate semialdehyde relative to the empty vector control.
FIG. 13 is a bar graph of the change in absorbance at 340 nm after 20 minutes, which is a measure of the consumption of NADPH and the activity of carboxylate reductases for converting 7-hydroxyheptanoate to 7-hydroxyheptanal relative to the empty vector control.
FIG. 14 is a bar graph of the change in absorbance at 340 nm after 20 minutes, which is a measure of the consumption of NADPH and the activity of carboxylate reductases for converting N7-acetyl-7-aminoheptanoate to N7-acetyl-7-aminoheptanal relative to the empty vector control.
FIG. 15 is a bar graph of the change in absorbance at 340 nm after 20 minutes, which is a measure of the consumption of NADPH and activity of carboxylate reductases for converting pimelate semialdehyde to heptanedial relative to the empty vector control.
FIG. 16 is a bar graph summarizing the percent conversion after 4 hours of pyruvate to L-alanine (mol/mol) as a measure of the ω-transaminase activity of the enzyme only controls (no substrate).
FIG. 17 is a bar graph of the percent conversion after 4 hours of pyruvate to L-alanine (mol/mol) as a measure of the ω-transaminase activity for converting 7-aminoheptanoate to pimelate semialdehyde relative to the empty vector control.
FIG. 18 is a bar graph of the percent conversion after 4 hours of L-alanine to pyruvate (mol/mol) as a measure of the a-transaminase activity for converting pimelate semialdehyde to 7-aminoheptanoate relative to the empty vector control.
FIG. 19 is a bar graph of the percent conversion after 4 hours of pyruvate to L-alanine (mol/mol) as a measure of the ω-transaminase activity for converting heptamethylenediamine to 7-aminoheptanal relative to the empty vector control.
FIG. 20 is a bar graph of the percent conversion after 4 hours of pyruvate to L-alanine (mol/mol) as a measure of the ω-transaminase activity for converting N7-acetyl-1,7-diaminoheptane to N7-acetyl-7-aminoheptanal relative to the empty vector control.
FIG. 21 is a bar graph of the percent conversion after 4 hours of pyruvate to L-alanine (mol/mol) as a measure of the ω-transaminase activity for converting 7-aminoheptanol to 7-oxoheptanol relative to the empty vector control.
FIG. 22 is a table of the conversion after 1 hour of pimeloyl-CoA methyl ester to pimeloyl-CoA by a pimeloyl-[acp] methyl ester methylesterase.
FIG. 23 is a table of the conversion after three hours of glutaryl-CoA and acetyl-CoA to 3-keotpimeloyl-CoA by a β-ketothiolase.



DETAILED DESCRIPTION
This document provides enzymes, non-natural pathways, cultivation strategies, feedstocks, host microorganisms and attenuations to the host's biochemical network, which generates a seven carbon chain aliphatic backbone from central metabolites in which one or two terminal functional groups may be formed leading to the synthesis of pimelic acid, 7-aminoheptanoic acid, heptamethylenediamine, 7-hydroxyheptanoic acid, or 1,7-heptanediol (referred to as “C7 building blocks” herein). As used herein, the term “central precursor” is used to denote any metabolite in any metabolic pathway shown herein leading to the synthesis of a C7 building block. The term “central metabolite” is used herein to denote a metabolite that is produced in all microorganisms to support growth.
Host microorganisms described herein can include endogenous pathways that can be manipulated such that one or more C7 building blocks can be produced. In an endogenous pathway, the host microorganism naturally expresses all of the enzymes catalyzing the reactions within the pathway. A host microorganism containing an engineered pathway does not naturally express all of the enzymes catalyzing the reactions within the pathway but has been engineered such that all of the enzymes within the pathway are expressed in the host.
The term “exogenous” as used herein with reference to a nucleic acid (or a protein) and a host refers to a nucleic acid that does not occur in (and cannot be obtained from) a cell of that particular type as it is found in nature or a protein encoded by such a nucleic acid. Thus, a non-naturally-occurring nucleic acid is considered to be exogenous to a host once in the host. It is important to note that non-naturally-occurring nucleic acids can contain nucleic acid subsequences or fragments of nucleic acid sequences that are found in nature provided the nucleic acid as a whole does not exist in nature. For example, a nucleic acid molecule containing a genomic DNA sequence within an expression vector is non-naturally-occurring nucleic acid, and thus is exogenous to a host cell once introduced into the host, since that nucleic acid molecule as a whole (genomic DNA plus vector DNA) does not exist in nature. Thus, any vector, autonomously replicating plasmid, or virus (e.g., retrovirus, adenovirus, or herpes virus) that as a whole does not exist in nature is considered to be non-naturally-occurring nucleic acid. It follows that genomic DNA fragments produced by PCR or restriction endonuclease treatment as well as cDNAs are considered to be non-naturally-occurring nucleic acid since they exist as separate molecules not found in nature. It also follows that any nucleic acid containing a promoter sequence and polypeptide-encoding sequence (e.g., cDNA or genomic DNA) in an arrangement not found in nature is non-naturally-occurring nucleic acid. A nucleic acid that is naturally-occurring can be exogenous to a particular host microorganism. For example, an entire chromosome isolated from a cell of yeast x is an exogenous nucleic acid with respect to a cell of yeast y once that chromosome is introduced into a cell of yeast y.
In contrast, the term “endogenous” as used herein with reference to a nucleic acid (e.g., a gene) (or a protein) and a host refers to a nucleic acid (or protein) that does occur in (and can be obtained from) that particular host as it is found in nature. Moreover, a cell “endogenously expressing” a nucleic acid (or protein) expresses that nucleic acid (or protein) as does a host of the same particular type as it is found in nature. Moreover, a host “endogenously producing” or that “endogenously produces” a nucleic acid, protein, or other compound produces that nucleic acid, protein, or compound as does a host of the same particular type as it is found in nature.
For example, depending on the host and the compounds produced by the host, a recombinant host can express an exogenous polypeptide having fatty acid O-methyltransferase activity.
For example, depending on the host and the compounds produced by the host, one or more of the following polypeptides may be expressed in the host in addition to a polypeptide having (i)fatty acid O-methyltransferase activity, (ii) thioesterase activity or a CoA-transferase activity, and (iii) CoA ligase activity: a pimelyl-[acp] methyl ester esterae, a (homo)ncitrate synthase, a (homo)ncitrate dehydratave, a (homo)aconitate hydratase, an iso(homo)ncitrate dehydrogenase, an decarboxylase such as an indolepyruvate decarboxylase, a β-ketothiolase, an acetyl-carboxylase, an acetoacetyl-CoA synthase, a 3-hydroxybutyryl-CoA dehydrogenase, an enoyl-CoA hydratase, a glutaryl-CoA dehydrogenase, an enoyl-CoA reductase, a trans-2-enoyl-CoA reductase, a glutaconyl-CoA decarboxylase, a β-ketoacyl-[acp] synthase, a 3-hydroxybutyryl-CoA dehydrogenase, a 2-hydroxyglutarate dehydrogenase, a 2-hydroxyglutaryl-CoA dehydratase, a glutarate semialdehyde dehydrogenase, a 4-hydroxy-2-oxoheptanedioate aldolase, a 2-oxo-hept-3-ene-1,7-dioate hydratase, a 2-enoate reductase, a 2-hydroxyglutarate dehydrogenase, a 2-hydroxyglutaryl-CoA dehydratase, a thioesterase, an aldehyde dehydrogenase, a 6-oxohexanoate dehydrogenase, a 7-oxoheptanoate dehydrogenase, a reversible CoA-ligase (e.g., a reversible succinyl-CoA-ligase), a CoA-transferase (e.g., a glutaconate CoA-transferase), an acetylating aldehyde dehydrogenase, a carboxylate reductase, 4-hydroxybutyrate dehydrogenase, a 5-hydroxypentanoate dehydrogenase, a 6-hydroxyhexanoate dehydrogenase, a ω-transaminase, a N-acetyl transferase, an alcohol dehydrogenase, or a deacetylase. In recombinant hosts expressing a carboxylate reductase, a phosphopantetheinyl transferase also can be expressed as it enhances activity of the carboxylate reductase.
For example, a recombinant host can include at least one exogenous nucleic acid encoding a (i) fatty acid O-methyltransferase, (ii) a thioesterase or CoA-transferase, and/or (iii) a CoA ligase. In some embodiments, a recombinant host includes an exogenous nucleic acid encoding a (i) fatty acid O-methyltransferase and a (ii) thioesterase or CoA-transferase, wherein the host produces 2(E)-heptenedioate methyl ester. In some embodiments, a recombinant host includes an exogenous nucleic acid encoding a fatty acid O-methyltransferase and a CoA ligase, wherein the host produces hept-2-enedioyl CoA methyl ester. In some embodiments, the recombinant host includes an exogenous nucleic acid encoding (i) a fatty acid O-methyltransferase, (ii) a thioesterase, and (iii) a CoA ligase, and produces hept-2-enedioyl CoA methyl ester. Such a host further can include an exogenous trans-2-enoyl-CoA reductase and an exogenous pimeloyl-[acp] methyl ester methylesterase, and further produce pimeloyl-CoA.
In some embodiments, the host can include one or more of the following exogenous enzymes used to produce glutaryl-CoA from 2-oxo-glutarate: (a) a homocitrate synthase, (b) a homocitrate dehydratase, (c) a homoaconitate hydratase, an (d) isohomocitrate dehydrogenase, (e) a decarboxylase such as indolepyruvate decarboxylase, (f) a glutarate-semialdehyde dehydrogenase, and (g) a glutarate:CoA ligase or CoA-transferase.
In some embodiments, the host can include one or more of the following exogenous enzymes used to produce glutaryl CoA from acetyl CoA: (a) a β-ketothiolase or an acetyl-carboxylase in combination with an acetoacetyl-CoA synthase. (b) a 3-hydroxybutyryl-CoA dehydrogenase, (c) an enoyl-CoA hydratase, and either (d) a glutaryl-CoA dehydrogenase in combination with an enoyl-CoA reductase or (e) a glutaconyl-CoA decarboxylase.
In some embodiments, the host can include one or more of the following exogenous enzymes used to produce 2-heptenedioyl-CoA from glutaryl CoA: a β-ketoacyl-[acp] synthase or β-ketothiolase, a 3-hydroxyacyl-CoA dehydrogenase, and an enoyl-CoA hydratase.
In some embodiments, the host can include one or more of the following exogenous enzymes used to convert 2-oxo-glutarate to hept-2-enedioyl-CoA via 2-oxo-pimelate as shown in FIG. 2: a homocitrate synthase, a homocitrate dehydratase, a homoaconitate hydratase, an isohomocitrate dehydrogenase, a 2-hydroxyglutarate dehydrogenase, a glutaconate CoA-transferase, and a 2-hydroxyglutaryl-CoA dehydratase.
In some embodiments, the host can include one or more of the following exogenous enzymes used to convert succinate semialdehyde to hept-2-enedioyl-CoA via 2-oxo-pimelate as shown in FIG. 3: a glutarate semialdehyde dehydrogenase, a 4-hydroxy-2-oxoheptanedioate aldolase, a 2-oxo-hept-3-ene-1,7-dioate hydratase, a 2-enoate reductase, a 2-hydroxyglutarate dehydrogenase, a glutaconate CoA-transferase, and a 2-hydroxyglutaryl-CoA dehydratase.
Such recombinant hosts further can include at least one exogenous nucleic acid encoding one or more of a thioesterase, an aldehyde dehydrogenase, a 7-oxoheptanoate dehydrogenase, a 6-oxohexanoate dehydrogenase, a 5-oxopentanoate dehydrogenase, a CoA-transferase, a reversible CoA-ligase, an acetylating aldehyde dehydrogenase, or a carboxylate reductase and produce pimelic acid or pimelate semialdehyde. For example, a recombinant host producing pimeloyl-CoA further can include a thioesterase, a reversible Co-ligase (e.g., a reversible succinyl-CoA ligase), or a CoA transferase (e.g., a glutaconate CoA-transferase) and produce pimelic acid. For example, a recombinant host producing pimeloyl-CoA further can include an acetylating aldehyde dehydrogenase and produce pimelate semilaldehyde. For example, a recombinant host producing pimelate further can include a carboxylate reductase and produce pimelate semialdehyde.
A recombinant hosts producing pimelic acid or pimelate semialdehyde further can include at least one exogenous nucleic acid encoding a ω-transaminase and produce 7-aminoheptanoate. In some embodiments, a recombinant host producing pimelate includes a carboxylate reductase and a ω-transaminase to produce 7-aminoheptanoate.
A recombinant host producing pimelate or pimelate semialdehyde further can include at least one exogenous nucleic acid encoding a 6-hydroxyhexanoate dehydrogenase, a 5-hydroxypentanoate dehydrogenase or a 4-hydroxybutyrate dehydrogenase, and produce 7-hydroxyheptanoic acid. In some embodiments, a recombinant host producing pimeloyl-CoA includes an acetylating aldehyde dehydrogenase, and a 6-hydroxyhexanoate dehydrogenase, a 5-hydroxypentanoate dehydrogenase or a 4-hydroxybutyrate dehydrogenase to produce 7-hydroxyheptanoate. In some embodiments, a recombinant host producing pimelate includes a carboxylate reductase and a 6-hydroxyhexanoate dehydrogenase, a 5-hydroxypentanoate dehydrogenase or a 4-hydroxybutyrate dehydrogenase to produce 7-hydroxyheptanoate.
A recombinant hosts producing 7-aminoheptanoate, 7-hydroxyheptanoate or pimelate semialdehyde further can include at least one exogenous nucleic acid encoding a ω-transaminase, a deacetylase, a N-acetyl transferase, or an alcohol dehydrogenase, and produce heptamethylenediamine. For example, a recombinant host producing 7-hydroxyheptanoate can include a carboxylate reductase with a phosphopantetheine transferase enhancer, a ω-transaminase and an alcohol dehydrogenase.
A recombinant host producing 7-hydroxyheptanoic acid further can include one or more of a carboxylate reductase with a phosphopantetheine transferase enhancer and an alcohol dehydrogenase, and produce 1,7-heptanediol.
Within an engineered pathway, the enzymes can be from a single source, i.e., from one species or genus, or can be from multiple sources, i.e., different species or genera. Nucleic acids encoding the enzymes described herein have been identified from various organisms and are readily available in publicly available databases such as GenBank or EMBL.
Any of the enzymes described herein that can be used for production of one or more C7 building blocks can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 1000%) to the amino acid sequence of the corresponding wild-type enzyme. It will be appreciated that the sequence identity can be determined on the basis of the mature enzyme (e.g., with any signal sequence removed) or on the basis of the immature enzyme (e.g., with any signal sequence included). It also will be appreciated that the initial methionine residue may or may not be present on any of the enzyme sequences described herein.
For example, a polypeptide having fatty acid O-methyltransferase activity described herein can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of a Mycobacterium marinum (see GenBank Accession No. ACC41782.1, SEQ ID NO: 1), a Mycobacterium smegmatis (see GenBank Accession No. ABK73223.1, SEQ ID NO: 2), or a Pseudomonas putida (see GenBank Accession No. CAA39234.1, SEQ ID NO: 3) methyltransferase. See, FIG. 9A.
For example, a polypeptide having thioesterase activity described herein can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%0, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of a Lactobacillus brevis (GenBank Accession No. ABJ63754.1, SEQ ID NO: 4) or a Lactobacillus plantarum (GenBank Accession No. CCC78182.1, SEQ ID NO: 5) acyl-[acp] thioesterase. See, FIGS. 9A and 9B.
For example, a polypeptide having pimelyl-[acp] methyl ester esterase activity described herein can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of an Escherichia coli pimelyl-[acp] methyl ester esterase (see GenBank Accession No. AAC76437.1, SEQ ID NO: 6). See, FIG. 9B.
For example, a polypeptide having carboxylate reductase activity described herein can have at least 700% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of a Mycobacterium marinum (see Genbank Accession No. ACC40567.1, SEQ ID NO: 7), a Mycobacterium smegmatis (see Genbank Accession No. ABK71854.1, SEQ ID NO: 8), a Segniliparus rugoslis (see Genbank Accession No. EFV11917.1, SEQ ID NO: 9), a Mycobacterium smegmatis (see Genbank Accession No. ABK75684.1, SEQ ID NO: 10), a Mycobacterium massiliense (see Genbank Accession No. EIV11143.1, SEQ ID NO: 11), or a Segniliparus rotundus (see Genbank Accession No. ADG98140.1, SEQ ID NO: 12) carboxylate reductase. See, FIGS. 9C-9H.
For example, a polypeptide having ω-transaminase activity described herein can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 920%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of a Chromobacterium violaceum (see Genbank Accession No. AAQ59697.1, SEQ ID NO: 13), a Pseudomonas aeruginosa (see Genbank Accession No. AAG08191.1, SEQ ID NO: 14), a Pseudomonas syringae (see Genbank Accession No. AAY39893.1, SEQ ID NO: 15), a Rhodobacter sphaeroides (see Genbank Accession No. ABA81135.1, SEQ ID NO: 16), an Escherichia coli (see Genbank Accession No. AAA57874.1, SEQ ID NO: 17), or a Vibrio fluvialis (see Genbank Accession No. AEA39183.1, SEQ ID NO: 18) ω-transaminase. See FIGS. 9I and 9J. Some of these ω-transaminases are diamine ω-transaminases.
For example, a polypeptide having phosphopantetheinyl transferase activity described herein can have at least 700 sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of a Bacillus subtilis phosphopantetheinyl transferase (see Genbank Accession No. CAA44858.1, SEQ ID NO: 19) or a Nocardia sp. NRRL 5646 phosphopantetheinyl transferase (see Genbank Accession No. AB183656.1, SEQ ID NO: 20). See, FIG. 9K.
For example, a polypeptide having thioesterase activity described herein can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of an Escherichia coli thioesterase encoded by tesB (see GenBank Accession No. AAA24665.1, SEQ ID NO: 21). See, FIG. 9K.
For example, a polypeptide having long-chain-fatty-acid-CoA ligase activity described herein can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of an Escherichia coli long-chain-fatty-acid-CoA ligase (see Genbank Accession No. CAA50321.1, SEQ ID NO: 22), or a Cupriavidus necator long-chain-fatty-acid-CoA ligase (see Genbank Accession No. CAJ95550.1, SEQ ID NO: 23).
For example, a polypeptide having glutaconate CoA-transferase activity described herein can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of an Acidaminococcus fermentans glutaconate CoA-transferase (see, e.g., Genbank Accession No. CAA57199.1 (GctA) and CAA57200.1 (GctB), SEQ ID NOs: 24 and 25, respectively).
For example, a polypeptide having enoyl-CoA reductase activity described herein can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of a Treponema denticola enoyl-CoA reductase (see, e.g., Genbank Accession No. AAS11092.1, SEQ ID NO: 26) or to the amino acid sequence of an Euglena gracilis enoyl-CoA reductase (see, e.g., Genbank Accession No. AAW66853.1, SEQ ID NO: 27).
For example, a polypeptide having enoyl-CoA reductase activity described herein can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of a Pseudomonas reinekei MTI β-ketothiolase (see, e.g., Genbank Accession No. ACZ63623.1, SEQ ID NO: 28), a Pseudomonas putida β-ketothiolase (see, e.g., Genbank Accession No. AAA85138.1, SEQ ID NO: 29), a Burkholderia xenovorans β-ketothiolase (see, e.g., Genbank Accession No. ABE33819.1, SEQ ID NO: 30), an Arthrobacter sp. β-ketothiolase (see, e.g., Genbank Accession No. ABK03524.1, SEQ ID NO: 31), a Burkholderia xenovorans β-ketothiolase (see, e.g., Genbank Accession No. ABE36495.1, SEQ ID NO: 32), a Geobacillus kaustophilus β-ketothiolase (see, e.g., Genbank Accession No. BAD75605.1, SEQ ID NO: 33), a Gordonia bronchialis β-ketothiolase (see, e.g., Genbank Accession ACY20886.1, SEQ ID NO: 34), a Citrobacter freundii β-ketothiolase (see, e.g., Genbank Accession KFB98168.1, SEQ ID NO: 35), a Burkholderia sp. β-ketothiolase (see, e.g., Genbank Accession ADG18081.1, SEQ ID NO: 36), a Beijerinckia indica β-ketothiolase (see, e.g., Genbank Accession ACB95386.1, SEQ ID NO: 37), an Arthrobacter arilaitensis β-ketothiolase (see, e.g., Genbank Accession CBT74677.1, SEQ ID NO: 38), a Cupriavidus necator β-ketothiolase (see, e.g., Genbank Accession AAC38322.1, SEQ ID NO: 39), and an Escherichia coli β-ketothiolase (see, e.g., Genbank Accession AAC74479.1, SEQ ID NO: 40).
The percent identity (homology) between two amino acid sequences can be determined as follows. First, the amino acid sequences are aligned using the BLAST 2 Sequences (Bl2seq) program from the stand-alone version of BLASTZ containing BLASTP version 2.0.14. This stand-alone version of BLASTZ can be obtained from Fish & Richardson's web site (e.g., www.fr.com/blast/) or the U.S. government's National Center for Biotechnology Information web site (www.ncbi.nlm.nih.gov). Instructions explaining how to use the Bl2seq program can be found in the readme file accompanying BLASTZ. Bl2seq performs a comparison between two amino acid sequences using the BLASTP algorithm. To compare two amino acid sequences, the options of Bl2seq are set as follows: -i is set to a file containing the first amino acid sequence to be compared (e.g., C:\seq1.txt); -j is set to a file containing the second amino acid sequence to be compared (e.g., C:\seq2.txt); -p is set to blastp; -o is set to any desired file name (e.g., C:\output.txt); and all other options are left at their default setting. For example, the following command can be used to generate an output file containing a comparison between two amino acid sequences: C:\Bl2seq -i c:\seq1.txt -j c:\seq2.txt -p blastp -o c:\output.txt. If the two compared sequences share homology (identity), then the designated output file will present those regions of homology as aligned sequences. If the two compared sequences do not share homology (identity), then the designated output file will not present aligned sequences. Similar procedures can be following for nucleic acid sequences except that blastn is used.
Once aligned, the number of matches is determined by counting the number of positions where an identical amino acid residue is presented in both sequences. The percent identity (homology) is determined by dividing the number of matches by the length of the full-length polypeptide amino acid sequence followed by multiplying the resulting value by 100. It is noted that the percent identity (homology) value is rounded to the nearest tenth. For example, 78.11, 78.12, 78.13, and 78.14 is rounded down to 78.1, while 78.15, 78.16, 78.17, 78.18, and 78.19 is rounded up to 78.2. It also is noted that the length value will always be an integer.
It will be appreciated that a number of nucleic acids can encode a polypeptide having a particular amino acid sequence. The degeneracy of the genetic code is well known to the art; i.e., for many amino acids, there is more than one nucleotide triplet that serves as the codon for the amino acid. For example, codons in the coding sequence for a given enzyme can be modified such that optimal expression in a particular species (e.g., bacteria or fungus) is obtained, using appropriate codon bias tables for that species.
Functional fragments of any of the enzymes described herein can also be used in the methods of the document. The term “functional fragment” as used herein refers to a peptide fragment of a protein that has at least 25% (e.g., at least: 30%; 40%; 50%; 60%; 70%; 75%; 80%; 85%; 90%; 91%; 92%; 93%; 94%; 95%; 96%; 97%; 98%; 99%; 100%; or even greater than 100%) of the activity of the corresponding mature, full-length, wild-type protein. The functional fragment can generally, but not always, be comprised of a continuous region of the protein, wherein the region has functional activity. Functional fragments are shorter than corresponding mature proteins but are generally at least 25 (e.g., at least: 30; 40; 50; 60; 70; 80, 90; 100; 120; 150; 200; 250; 300; 450; 500; 800; or more) amino acids long.
This document also provides (i) functional variants of the enzymes used in the methods of the document and (ii) functional variants of the functional fragments described above. Functional variants of the enzymes and functional fragments can contain additions, deletions, or substitutions relative to the corresponding wild-type sequences. Enzymes with substitutions will generally have not more than 50 (e.g., not more than one, two, three, four, five, six, seven, eight, nine, ten, 12, 15, 20, 25, 30, 35, 40, or 50) amino acid substitutions (e.g., conservative substitutions). This applies to any of the enzymes described herein and functional fragments. A conservative substitution is a substitution of one amino acid for another with similar characteristics. Conservative substitutions include substitutions within the following groups: valine, alanine and glycine; leucine, valine, and isoleucine; aspartic acid and glutamic acid; asparagine and glutamine; serine, cysteine, and threonine; lysine and arginine; and phenylalanine and tyrosine. The nonpolar hydrophobic amino acids include alanine, leucine, isoleucine, valine, proline, phenylalanine, tryptophan and methionine. The polar neutral amino acids include glycine, serine, threonine, cysteine, tyrosine, asparagine and glutamine. The positively charged (basic) amino acids include arginine, lysine and histidine. The negatively charged (acidic) amino acids include aspartic acid and glutamic acid. Any substitution of one member of the above-mentioned polar, basic or acidic groups by another member of the same group can be deemed a conservative substitution. By contrast, a nonconservative substitution is a substitution of one amino acid for another with dissimilar characteristics.
Deletion variants can lack one, two, three, four, five, six, seven, eight, nine, ten, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 amino acid segments (of two or more amino acids) or non-contiguous single amino acids. Additions (addition variants) include fusion proteins containing: (a) any of the enzymes described herein or a fragment thereof; and (b) internal or terminal (C or N) irrelevant or heterologous amino acid sequences. In the context of such fusion proteins, the term “heterologous amino acid sequences” refers to an amino acid sequence other than (a). A heterologous sequence can be, for example a sequence used for purification of the recombinant protein (e.g., FLAG, polyhistidine (e.g., hexahistidine), hemagglutinin (HA), glutathione-S-transferase (GST), or maltose binding protein (MBP)). Heterologous sequences also can be proteins useful as detectable markers, for example, luciferase, green fluorescent protein (GFP), or chloramphenicol acetyl transferase (CAT). In some embodiments, the fusion protein contains a signal sequence from another protein. In certain host cells (e.g., yeast host cells), expression and/or secretion of the target protein can be increased through use of a heterologous signal sequence. In some embodiments, the fusion protein can contain a carrier (e.g., KLH) useful, e.g., in eliciting an immune response for antibody generation) or ER or Golgi apparatus retention signals. Heterologous sequences can be of varying length and in some cases can be a longer sequences than the full-length target proteins to which the heterologous sequences are attached.
Engineered hosts can naturally express none or some (e.g., one or more, two or more, three or more, four or more, five or more, or six or more) of the enzymes of the pathways described herein. Thus, a pathway within an engineered host can include all exogenous enzymes, or can include both endogenous and exogenous enzymes. Endogenous genes of the engineered hosts also can be disrupted to prevent the formation of undesirable metabolites or prevent the loss of intermediates in the pathway through other enzymes acting on such intermediates. Engineered hosts can be referred to as recombinant hosts or recombinant host cells. As described herein recombinant hosts can include nucleic acids encoding one or more of a methyltransferase, an esterase, a synthase, a dehydratase, a hydratase, a dehydrogenase, a thioesterase, a reversible CoA-ligase, a CoA-transferase, a reductase, deacetylase, N-acetyl transferase or a ω-transaminase as described in more detail below.
In addition, the production of one or more C7 building blocks can be performed in vitro using the isolated enzymes described herein, using a lysate (e.g., a cell lysate) from a host microorganism as a source of the enzymes, or using a plurality of lysates from different host microorganisms as the source of the enzymes.
Biosynthetic Methods
The present document provides methods of shielding a carbon chain aliphatic backbone, functionalized with terminal carboxyl groups, in a recombinant host. The method can include enzymatically converting a n-carboxy-2-enoic acid to a n-carboxy-2-enoate methyl ester in the host using a polypeptide having the activity of a fatty acid O-methyltransferase, wherein n+1 reflects length of the carbon chain aliphatic backbone. For example, the n-carboxy-2-enoic acid can be four to 18, four to 16, four to 14, four to 12, four to 10, five to 10, five to nine, or five to eight carbons in length such as 2(E)-heptenedioic acid, and can be enzymatically converted to the corresponding methyl ester, e.g., 2(E)-heptenedioate methyl ester, The polypeptide having fatty acid O-methyltransferase activity can be classified under EC 2.1.1.15. In some embodiments, the polypeptide having fatty acid O-methyltransferase activity has at least 70% sequence identity to an amino acid sequence set forth in SEQ ID NO: 1, SEQ ID NO: 2, or SEQ ID NO: 3.
In some embodiments, the method further includes enzymatically converting 2(E)-heptenedioate methyl ester to pimeloyl-CoA. For example, the method further can include enzymatically converting pimeloyl-CoA to a product selected from the group consisting of pimelic acid, 7-aminoheptanoate, 7-hydroxyheptanoate, heptamethylenediamine, and 1,7-heptanediol, for example, using one or more polypeptides having thioesterase, reversible CoA-ligase, glutaconate CoA-transferase, ω-transaminase, 6-hydroxyhexanoate dehydrogenase, 5-hydroxypentanoate dehydrogenase, 4-hydroxybutyrate dehydrogenase, alcohol dehydrogenase, carboxylate reductase or alcohol dehydrogenase activity.
The present document further provides methods of producing 2(E)-heptenedioyl-CoA methyl ester in a recombinant host. The method can include enzymatically converting 2(E)-heptenedioate to 2(E)-heptenedioate methyl ester in the recombinant host using a polypeptide having fatty acid O-methyltransferase activity. The polypeptide having fatty acid O-methyltransferase activity can be classified under EC 2.1.1.15. In some embodiments, the polypeptide having fatty acid O-methyltransferase activity has at least 70% sequence identity to an amino acid sequence set forth in SEQ ID NO: 1, SEQ ID NO: 2, or SEQ ID NO: 3. The method further can include enzymatically converting 2(E)-heptenedioate methyl ester to pimeloyl-CoA methyl ester.
In some embodiments, 2(E)-heptenedioate is enzymatically produced from 2(E)-heptenedioyl-CoA. For example, a polypeptide having thioesterase or CoA-transferase activity can enzymatically convert 2(E)-heptenedioyl-CoA to 2(E)-heptenedioate. In some embodiments, the polypeptide having thioesterase activity has at least 70% sequence identity to an amino acid sequence set forth in SEQ ID NO: 4 or SEQ ID NO: 5. In some embodiments, the polypeptide having CoA-transferase activity has at least 70% sequence identity to an amino acid sequence set forth in SEQ ID NO: 24 or SEQ ID NO: 25.
In some embodiments, 2(E)-heptenedioate methyl ester is enzymatically converted to 2(E)-heptenedioyl-CoA methyl ester using a polypeptide having CoA ligase activity classified under EC 6.2.1.-, e.g., EC 6.2.1.2 or EC 6.2.1.3.
In some embodiments, the method further includes enzymatically converting 2(E)-heptenedioyl-CoA methyl ester to pimeloyl-CoA methyl ester. In some embodiments, a polypeptide having trans-2-enoyl-CoA reductase activity enzymatically converts 2(E)-heptenedioyl-CoA methyl ester to pimeloyl-CoA methyl ester.
In some embodiments, the method further includes enzymatically converting pimeloyl-CoA methyl ester to pimeloyl-CoA. In some embodiments, a polypeptide having pimelyl-[acp] methyl ester esterase activity enzymatically converts pimeloyl-CoA methyl ester to pimeloyl-CoA. In some embodiments, the polypeptide having pimelyl-[acp] methyl ester esterase activity has at least 70% sequence identity to the amino acid sequence set forth in SEQ ID NO: 6.
In some embodiments, the method further includes enzymatically converting pimeloyl-CoA to a product selected from the group consisting of pimelic acid, 7-aminoheptanoate, 7-hydroxyheptanoate, heptamethylenediamine, and 1,7-heptanediol. In some embodiments, the method comprises enzymatically converting pimeloyl-CoA to pimelic acid using a polypeptide having thioesterase, reversible CoA-ligase, or glutaconate CoA-transferase activity.
In some embodiments, the method further includes enzymatically converting pimelic acid to pimelate semialdehyde using a polypeptide having carboxylate reductase activity. In some embodiments, the polypeptide having carboxylate reductase activity has at least 70% sequence identity to an amino acid sequence set forth in SEQ ID NOs: 7 to 12.
In some embodiments, the method includes enzymatically converting pimeloyl-CoA to pimelate semialdehyde using a polypeptide having acetylating aldehyde dehydrogenase activity. In some embodiments, the method further includes enzymatically converting pimelate semialdehyde to pimelic acid using a polypeptide having 5-oxopentanoate dehydrogenase, 6-oxohexanoale dehydrogenase, 7-oxoheptanoate dehydmrgenase, or aldehyde dehydrogenase activity.
In some embodiments, the method further includes enzymatically converting pimelate semialdehyde to 7-aminoheptanoate using a polypeptide having ω-transaminase activity. In some embodiments, the polypeptide having ω-transaminase activity has at least 70% sequence identity to an amino acid sequence set forth in SEQ ID NOs: 13 to 18.
In some embodiments, the method further includes enzymatically converting pimelate semialdehyde to heptamethylenediamine using a polypeptide having ω-transaminase activity.
In some embodiments, the method further includes enzymatically converting pimelate semialdehyde to 7-hydroxyheptanoate using a polypeptide having 6-hydroxyhexanoate dehydrogenase, 5-hydroxypentanoate dehydrogenase, 4-hydroxybutyrate dehydrogenase, or alcohol dehydrogenase activity.
In some embodiments, the method further includes enzymatically converting 7-hydroxyheptanoate to 1,7-heptanediol using a polypeptide having carboxylate reductase or alcohol dehydrogenase activity.
In some embodiments, one or more steps of the method are performed by fermentation. In some embodiments, the host is subjected to a cultivation strategy under aerobic, anaerobic, micro-aerobic, or mixed oxygen/denitrification cultivation conditions. In some embodiments, the host is cultured under conditions of phosphate, oxygen, and/or nitrogen limitation. In some embodiments, the host is retained using a ceramic membrane to maintain a high cell density during fermentation.
In some embodiments, the principal carbon source fed to the fermentation derives from biological or non-biological feedstocks. In some embodiments, the biological feedstock is, or derives from, monosaccharides, disaccharides, lignocellulose, hemicellulose, cellulose, lignin, levulinic acid, formic acid, triglycerides, glycerol, fatty acids, agricultural waste, condensed distillers' solubles, or municipal waste. In some embodiments, the non-biological feedstock is, or derives from, natural gas, syngas, CO2/H2, methanol, ethanol, benzoate, non-volatile residue (NVR) caustic wash waste stream from cyclohexane oxidation processes, or terephthalic acid/isophthalic acid mixture waste streams.
In some embodiments, the host comprises one or more polypeptides having attenuated polyhydroxyalkanoate synthase, acetyl-CoA thioesterase, acetyl-CoA specific β-ketothiolase, phosphotransacetylase forming acetate, acetate kinase, lactate dehydrogenase, menaquinol-fumarate oxidoreductase, 2-oxoacid decarboxylase producing isobutanol, alcohol dehydrogenase forming ethanol, triose phosphate isomerase, pyruvate decarboxylase, glucose-6-phosphate isomerase, transhydrogenase dissipating the NADPH imbalance, glutamate dehydrogenase dissipating the NADPH imbalance, NADH/NADPH-utilizing glutamate dehydrogenase, pimeloyl-CoA dehydrogenase; acyl-CoA dehydrogenase accepting C7 building blocks and central precursors as substrates; glutaryl-CoA dehydrogenase; or pimeloyl-CoA synthetase activity.
In some embodiments, the host overexpresses one or more genes encoding a polypeptide having acetyl-CoA synthetase; 6-phosphogluconate dehydrogenase; transketolase; puridine nucleotide transhydrogenase; formate dehydrogenase; glyceraldehyde-3P-dehydrogenase; malic enzyme; glucose-6-phosphate dehydrogenase; fructose 1,6 diphosphatase; L-alanine dehydrogenase; PEP carboxylase, pyruvate carboxylase; PEP carboxykinase; PEP synthase; L-glutamate dehydrogenase specific to the NADPH used to generate a co-factor imbalance; methanol dehydrogenase, formaldehyde dehydrogenase, lysine transporter; dicarboxylate transporter; S-adenosylmethionine synthetase; 3-phosphoglycerate dehydrogenase; 3-phosphoserine aminotransferase; phosphoserine phosphatase; or a multidrug transporter activity.
In some embodiments, the host is a prokaryote, e.g., Escherichia coli, Clostridium ljungdahlii, Clostridium autoethanogenum, Clostridium kluyveri, Corynebacterium glutamicum, Cupriavidus necator, Cupriavidus metallidurans, Pseudomonas fluorescens, Pseudomonas putida, Pseudomonas oleavorans, Delftia acidovorans, Bacillus subtillis, Lactobacillus delbrueckii, Lactococcus lactis, and Rhodococcus equi. 
In some embodiments, the host is a eukaryote, e.g., Aspergillus niger, Saccharomyces cerevisiae, Pichia pastoris, Yarrowia lipolytica, Issathenkia orientalis, Debaryomyces hansenii, Arxula adenoinivorans, and Kluyveromyces lactis. 
Enzymes Converting 2(E)-heptenedioyl-CoA to 2(E)-heptenedioyl-CoA methyl ester
As depicted in FIGS. 1 to 3, a 2(E)-heptenedioate methyl ester can be formed from 2(E)-heptenedioate using a fatty acid O-methyltransferase, such as the fatty acid O-methyltransferase classified, for example, under EC 2.1.1.15. For example, the fatty acid O-methyltransferase can be obtained from Mycobacterium marinum M (GenBank Accession No. ACC41782.1. SEQ ID NO: 1); Mycobacterium smegmatis (see GenBank Accession No. ABK73223.1, SEQ ID NO: 2), or Pseudomonas putida (see GenBank Accession No. CAA39234.1, SEQ ID NO: 3).
2(E)-heptenedioate methyl ester can be converted to 2(E)-heptenedioyl-CoA methyl ester using, for example, a CoA ligase classified, for example, under EC 6.2.1.-. In some embodiments, a butyrate-CoA ligase classified under EC 6.2.1.2 or a long-chain-fatty-acid-CoA ligase classified under EC 6.2.1.3 such as the long chain fatty acid CoA-ligase from Escherichia coli (Genbank Accession No. CAA50321.1, SEQ ID NO: 22) or Cupriavidus necator (Genbank Accession No. CAJ95550.1, SEQ ID NO: 23) can be used to convert 2(E)-heptenedioate methyl ester to 2(E)-heptendioyl-CoA methyl ester. See, FIGS. 1 to 3.
In some embodiments, 2(E)-heptenedioate can be formed from 2(E)-heptenedioyl-CoA (also known as 2,3-dehydropimeloyl-CoA) using, for example, a thioesterase classified under EC 3.1.2.-, such as the acyl-[acp] thioesterase from Lactobacillus brevis (GenBank Accession No. ABJ63754.1, SEQ ID NO: 4) or from Lactobacillus plantarum (GenBank Accession No. CCC78182.1, SEQ ID NO: 5). Such acyl-[acp] thioesterases have C6-C8 chain length specificity (see, for example, Jing et al., 2011, BMC Biochemistry, 12(44)). See, e.g., FIG. 1.
In some embodiments, 2(E)-heptenedioate can be formed from 2(E)-heptenedioyl-CoA using, for example, a CoA-transferase (e.g., a glutaconate CoA-transferase) classified, for example, under EC 2.8.3.12 such as the gene product of GctAB from Acidaminococcus fermentans (Genbank Accession No. CAA57199.1 (GctA) & CAA57200.1 (GctB), SEQ ID NOs: 24 and 25, respectively). See, for example, Buckel et al., 1981, Eur. J. Biochem., 118:315-321. See, e.g., FIGS. 2 and 3.
Enzymes Producing 2(E)-Heptenedioyl-CoA from Glutaryl-CoA
As depicted in FIG. 1, glutaryl-CoA can be formed from the central metabolites 2-oxoglutarate or acetyl-CoA via carbon chain elongation (i) associated with lysine biosynthesis via α-aminoadipate or (ii) associated with cyclohexane carboxylate biosynthesis in Synthrophus aciditrophicus. Glutaryl-CoA can be converted to 2(E)-heptenedioyl-CoA using a (i) β-ketoacyl-[acp] synthase or β-ketothiolase, (ii) a 3-hydroxybutyryl-CoA dehydrogenase, and a (iii) an enoyl-CoA hydratase.
For example, glutaryl-CoA can be formed via C1 carbon chain elongation associated with lysine biosynthesis via α-aminoadipate, which comprises using (i) a homocitrate synthase, (ii) a homocitrate dehydratase and a homoaconitate hydratase, (iii) an isohomocitrate dehydrogenase, (iv) an decarboxylase such as an indolepyruvate decarboxylase, (vi) a glutarate-semialdehyde dehydrogenase and (v) a glutarate:CoA ligase. See, e.g., FIG. 1.
For example, glutaryl-CoA can be formed via CoA-dependent carbon chain elongation associated with cyclohexane carboxylate biosynthesis in Synthrophus aciditrophicus which comprises using (i) a β-ketothiolase or an acetyl-carboxylase in combination with an acetoacetyl-CoA synthase, (ii) a 3-hydroxybutyl-CoA dehydrogenase, (iii) an enoyl-CoA hydratave, and either (iv) a glutaryl-CoA dehydrogenase in combination with an enoyl-CoA reductase or a trans-2-enoyl-CoA reductase or (v) a glutaconyl-CoA decarboxylase. See, e.g., FIG. 1.
In some embodiments, a (homo)ncitrate synthase can be classified, for example, under EC 2.3.3.14 or EC 2.3.3.13, such as the gene product of aksA from Methanocaldococcus jannaschii (see Genbank Accession No. AAB98494.1).
In some embodiments, the combination of (homo)ncitrate dehydratase and (homo)naconitate hydratase can be classified, for example, under EC 4.2.1.- (e.g., EC 4.2.1.114, EC 4.2.1.36 or EC 4.2.1.33), such as the gene product of aksD from Methanocaldococcus jannaschii (see, Genbank Accession No. AAB99007.1) or gene product of aksE from Methanocaldococcus jannaschii (see, Genbank Accession No. AAB99277.1). The gene products of aksD and aksE are subunits of an enzyme classified under EC 4.2.1.114. The gene products of LeuC and LeuD are subunits of an enzyme classified under EC 4.2.1.33.
In some embodiments, an iso(homo)ncitrate dehydrogenase can be classified, for example, under EC 1.1.1.- such as EC 1.1.1.85, EC 1.1.1.87 or EC 1.1.1.286, such as the gene product of aksF from Methanocaldococcus jannaschii (see, Genbank Accession No. ACA28837.1), the gene product of LYS12 from Saccharomyces cerevisiae (See Genbank Accession No. CAA86700.1) or hicdh from Thermus thermophiles (see Genbank Accession No. BAB88861.1).
In some embodiments, 2-oxo-adipate can be decarboxylated by a decarboxylase classified, for example, under EC 4.1.1.43, EC 4.1.1.72, or EC 4.1.1.74 such as the indole-3-pyruvate decarboxylase from Salmonella typhimurium (see, for example. Genbank Accession No. CAC48239.1). A mutant variant of the indolepyruvate decarboxylase from Salmonella typhimurium was engineered successfully to selectively accept longer chain length substrates. The L544A mutation of the sequence provided in Genbank Accession No. CAC48239.1 allowed for 567 times higher selectivity towards the C7 2-oxoacid than towards the C5 2-oxoacid (see, Xiong et al., 2012, Scientific Reports, 2: 311). The 2-oxoglutarate dehydrogenase complex has demonstrated activity for 2-oxoglutarate and 2-oxoadipate (Bunik et al., 2000, Eur. J. Biochem., 267, 3583-3591).
2-oxo-adipate also can be decarboxylated by a 2-oxoglutarate dehydrogenase complex comprised of enzymes homologous to enzymes classified, for example, under EC 1.2.4.2, EC 1.8.1.4, and EC 2.3.1.61. The 2-oxoglutarate dehydrogenase complex contains multiple copies of a 2-oxoglutarate dehydrogenase classified, for example, under EC 1.2.4.2 bound to a core of dihydrolipoyllysine-residue succinyltransferases classified, for example, under EC 2.3.1.61, which also binds multiple copies of a dihydrolipoyl dehydrogenase classified, for example, under EC 1.8.1.4.
In some embodiments, a 5-oxopentanoate dehydrogenase (e.g., a glutarate semialdehyde dehydrogenase) can be classified, for example under EC 1.2.1.- (e.g., EC 1.2.1.20, EC 1.2.1.16 or EC 1.2.1.79) such as the gene product of CpnE (see, for example, Iwaki et al., 2002, Appl. Environ. Microbiol., 68(11):5671-5684).
In some embodiments, a glularate CoA ligase can be classified, for example, under EC 6.2.1.6.
In some embodiments, a β-ketothiolase can be classified under EC 2.3.1.- (e.g., EC 2.3.1.9, EC 2.3.1.16, or EC 2.3.174). For example, a β-ketothiolase can be classified under EC 2.3.1.9, such as the gene product of atoB or phaA. The β-ketothiolase encoded by atoB or phaA accepts acetyl-CoA as substrates, forming acetoacetyl-CoA (see, Haywood et al., 1988, supra; Slater et al., 1998, supra). The β-ketothiolase encoded by paaJ (see, e.g., Genbank Accession No. AAC74479.1), catF and pcaF can be classified under, for example, EC 2.3.1.174. The β-ketothiolase encoded by paaJ condenses acetyl-CoA and succinyl-CoA to 3-oxoadipyl-CoA (see, for example, Fuchs et al., 2011, Nature Reviews Microbiology, 9, 803-816; Göbel et al., 2002, J. Bacteriol., 184(1), 216-223). A homologue of paaJ in Synthrophus aciditrophicus catalyses the condensation of acetyl-CoA and glutaryl-CoA to 3-oxopimeloyl-CoA such as Genbank Accession No. ABC78517.1 or Genbank Accession No. ABC78881.1. Alternately, a β-ketoacyl-[acp]homologue of paaJ in S. aciditrophicus catalyses the condensation of acetyl-CoA and glutaryl-CoA to 3-oxopimeloyl-CoA.
An acetyl-CoA carboxylase can be classified under EC 6.4.1.2 and an acetoacetyl-CoA synthase can be classified under EC 2.3.1.194. Conversion of acetyl-CoA to malonyl-CoA by an acetyl-CoA carboxylase has been shown to increase the rate of fatty acid synthesis (Davis et al., J. Biol. Chem., 2000, 275(37), 28593-28598). It has been demonstrated that acetoacetyl-CoA synthase may be used as an irreversible substitute for the gene product of phaA in the carbon chain elongation associated with polyhydroxybutyrate synthesis (Matsumoto et al., Biosci. Biotechnol. Biochem., 2011, 75(2), 364-366).
In some embodiments, a 3-hydroxybutyryl-CoA dehydrogenase (also can be referred to as a 3-hydroxyacyl-CoA dehydrogenase) can be classified under EC 1.1.1.157 such as the gene product hbd (see, for example, Shen et al., Appl. Environ. Microbiol., 2011, 77(9), 2905-2915; Budde et al., J. Bacteriol., 2010, 192(20), 5319-5328) or the gene product of paaH (Teufel et al., 2010, Proc. Natl. Acad Sci. 107(32), 14390-14395).
In some embodiments, an enoyl-CoA hydratase can be classified under EC 4.2.1.17, such as the gene product of crt (see, for example, Shen et al., 2011, supra; Fukui et al., J. Bacteriol., 1998, 180(3), 667-673) or the gene product of paaF (see, for example, Fuchs et al., 2011, supra). Homologs of paaF in S. acidiirophicus include the enoyl-CoA hydratase of Genbank Accession No. ABC77794.1 or the enoyl-CoA dehydratase of Genbank Accession No. ABC78950.1.
In some embodiments, a reversible glutaconyl-CoA decarboxylase that relies on a Na+ membrane pump can be classified, for example, under EC 4.1.1.70 (see Mouttaki et al., Appl. Environ. Microbiol., 2007, 73(3), 930-938). The EC 4.1.1.70 enzyme activity is associated with the following subunits in S. aciditrophicus, viz. Genbank Accession Nos. (1) ABC77900.1, (2) ABC76114.1 and (3) ABC77898.1.
In some embodiments, an enoyl-[acp] reductase can be classified under EC 1.3.1.- (e.g., EC 1.3.1.9) such as the enoyl-[acp] reductase obtained from S. aciditrophicus or the gene product of FabI (Genbank Accession No: CAB13029.2) from Bacillus subtillis (see, for example, Heath et al., 2000, J. Biol. Chem., 275(51), 40128-33). The enovl-[acp] reductase involved in fatty acid synthesis in S. aciditrophicus likely accepts CoA activated dicarboxylic acids (Mouttaki et al., 2007, supra).
In some embodiments, a trans-2-enoyl-CoA reductase can be classified, for example, under EC 1.3.1.44, such as the gene product of ter (Genbank Accession No. AAW66853.1) (Hoffmeister et al., 2005, J. Biol. Chem., 280(6), 4329-4338; Shen et al., 2011, supra) or tdter (Genbank Accession No. AAS 11092.1) (Bond-Watts et al., Biochemistry, 2012, 51, 6827-6837).
A β-ketoacyl-[acp] synthase can be classified, for example, under, EC 2.3.1.41, EC 2.3.1.179, or EC 2.3.1.180. The β-ketothiolases and β-ketoacyl-[acp] synthases involved in fatty acid synthesis in S. aciditrophicus likely accept CoA activated dicarboxylic acids (Mouttaki et al., Appl. Environ. Microbiol., 2007, 73(3), 930-938).
Enzymes Producing 2(E)-Heptenedioyl-CoA from 2-Oxo-Pimelate
As depicted in FIG. 2, 2-oxo-pimelate can be formed from the central metabolite 2-oxoglutarate via two rounds of carbon chain elongation associated with lysine biosynthesis via α-aminoadipate, where each round of elongation comprises using (i) a homocitrate synthase, (ii) a homocitrate dehydratase and a homoaconitate hydratase, and (iii) an isohomocitrate dehydrogenase. The homocitrate synthase, a homocitrate dehydratase, homoaconitate hydratase, and isohomocitrate dehydrogenase are described above. 2-oxo-pimelate also can be formed from succinate semialdehyde using a 4-hydroxy-2-oxoheptanedioate aldolase, a 2-oxo-hept-3-ene-1, 7-dioate hydratase, and a 2-enoate reductase as shown in FIG. 3.
2-oxo-pimelate can be converted to 2(E)-heptenedioyl-CoA using (i) a 2-hydroxyglutarate dehydrogenase or (ii) a lactate dehydrogenase. (ii) a CoA-transferase such as a glutaconate CoA-transferase, and (iii) a 2-hydroxyglutaryl-CoA dehydratase or a 2-hydroxvisocaproyl-CoA dehydratase. See, FIGS. 2 and 3.
A 2-hydroxyglutarate dehydrogenase can be classified, for example under EC 1.1.1.-(337) such as the gene product of HgdH or IdhA. See, Djurdjevic et al, 2011, Appl. Environ. Microbiol., 77(1), 320-322 and Kim et al., 2005, FEBS Journal, 272, 550-561.
A CoA-transferase such as a glutaconate CoA-transferase can be classified, for example, under EC 2.8.3.12 and can be obtained from Acidaminococcus fermentans (see, e.g., SEQ ID NOs: 24 and 25). See, for example, Buckel et al., 1981, Eur. J. Biochem., 118:315-321.
A 2-hydroxyglutaryl-CoA dehydratase can be classified, for example, under EC 4.2.1.- such as the gene product of HgdAB (Genbank Accession Nos. AAD31677.1 and AAD31675.1) in combination with an activator, the gene product of HgdC (Genbank Accession No. CAA42196.1). The HgdAB gene product contains subunits A and B. See, Djurdjevic et al, 2011, supra. A 2-hydroxyisocaproyl-CoA dehydratase can be classified, for example, under EC 4.2.1.- such as the gene product of hadBC (Genbank Accession Nos. AAV40819.1 & AAV40820.1) or hadI (Genbank Accession No. AAV40818.1).
A 4-hydroxy-2-oxoheptanedioate aldolase can be classified, for example, under EC 4.1.2.52 such as the gene product of HpaI. See Genbank Accession No. CAA87759.1.
A 2-oxo-hept-3-ene-1,7-dioate hydratase can be classified, for example, under EC 4.2.1.- such as the gene product of HpaH. See GenBank Accession No. AAB91474.1.
In some embodiments, a 2-enoate reductase may be classified under EC 1.3.1.- such as EC 1.3.1.31 or EC 1.6.99.1 such as originating from Bacillus subtilis (Genbank Accession No. BAA12619.1), Pseudomonas putida Genbank Accession No. AAN66878.1), Kluyveromyces lactis (Genbank Accession No. AAA98815.1), Lactobacillus casei (Genbank Accession No. AGP69310.1), Saccharomyces pastorianus (Genbank Accession No. CAA37666.1), Thermoanaerobacter pseudethanolicus (Genbank Accession No. ABY93685.1), or Enterobacter cloacae (Genbank Accession No. AAB38683.1) (Gao et al., 2012, Enzyme Microb. Technol., 51(1), 26-34).
Enzymes Facilitating Introduction of Terminal Functional Groups in the Biosynthesis of a C7 Building Block
In some embodiments, a carboxylate reductase facilitates the generation of a terminal aldehyde group for subsequent conversion to an amine group by an ω-transaminase or to a hydroxyl group by an alcohol dehydrogenase. The carboxylate reductase can be obtained, for example, from Mycobacterium marimum (Genbank Accession No. ACC40567.1, SEQ ID NO: 7), Mycobacterium smegmatis (Genbank Accession No. ABK71854.1, SEQ ID NO: 8), Segniliparus rugosus (Genbank Accession No. EFV11917.1, SEQ ID NO: 9), Mycobacterium smegmatis (Genbank Accession No. ABK75684.1, SEQ ID NO: 10), Mycobacterium massiliense (Genbank Accession No. EIV11143.1, SEQ ID NO: 11), or Segniliparus rotundus (Genbank Accession No. ADG98140.1, SEQ ID NO: 12). See, e.g., FIGS. 4 to 8.
The carboxylate reductase encoded by the gene product of car and enhancer npt has broad substrate specificity, including terminal difunctional C4 and C5 carboxylic acids (Venkitasubramanian et al., Enzyme and Microbial Technology, 2008, 42, 130-137).
Enzymes Generating the Terminal Carboxyl Groups in the Biosynthesis of C7 Building Blocks
As depicted in FIG. 4, a terminal carboxyl group can be enzymatically formed using a thioesterase, an aldehyde dehydrogenase, a 7-oxoheptanoate dehydrogenase, a 6-oxohexanoate dehydrogenase, a CoA-transferase or a reversible CoA-ligase.
In some embodiments, the first terminal carboxyl group leading to the synthesis of a C7 building block is enzymatically formed by a pimelyl-[acp] methyl ester esterase classified, for example, under EC 3.1.1.85 such as the gene product of bioH (GenBank Accession No. AAC76437.1, SEQ ID NO: 6). See, FIGS. 1 and 2.
In some embodiments, the second terminal carboxyl group leading to the synthesis of a C7 building block is enzymatically formed by a thioesterase classified under EC 3.1.2.-, such as the gene product of YciA, tesB (Genbank Accession No. AAA24665.1, SEQ ID NO: 21), Acot13 or originating from Lactobacillus brevis (GenBank Accession No. ABJ63754.1, SEQ ID NO: 4) or from Lactobacillus plantarum (GenBank Accession No. CCC78182.1, SEQ ID NO: 5) (see, for example, Cantu et al., Protein Science, 2010, 19, 1281-1295; Zhuang et al., Biochemistry, 2008, 47(9), 2789-2796; Naggert et al., J. Biol. Chem., 1991, 266(17), 11044-11050; or Jing et al., 2011, BMC Biochemistry, 12(44)).
In some embodiments, the second terminal carboxyl group leading to the synthesis of pimelic acid is enzymatically formed by an aldehyde dehydrogenase classified, for example, under EC 1.2.1.3 (see, for example, Guerrillot & Vandecasteele, Eur. J. Biochem., 1977, 81, 185-192).
In some embodiments, the second terminal carboxyl group leading to the synthesis of pimelic acid is enzymatically formed by a dehydrogenase classified under EC 1.2.1.-(.g., EC 1.2.1.16, EC 1.2.1.20, EC 1.2.1.79, EC 1.2.1.3 or EC 1.2.1.63) such as 5-oxopentanoate dehydrogenase (e.g., the gene product of CpnE from Comamonas sp.), 6-oxohexanoate dehydrogenase (e.g., the gene product of ChnE from Acinetobacter sp.) or a 7-oxoheptanoate dehydrogenase (e.g., the gene product of ThnG from Sphingomonas macrogolitabida). See, for example, Iwaki et al., Appl. Environ. Microbiol., 1999, 65(11), 5158-5162; Iwaki et al., Appl. Environ. Microbiol., 2002, 68(11), 5671-5684; or López-Sánchez et al., Appl. Environ. Microbiol., 2010, 76(1), 110-118. For example, a 6-oxohexanoate dehydrogenase can be classified under EC 1.2.1.63. For example, a 7-oxoheptanoate dehydrogenase can be classified under EC 1.2.1.-.
In some embodiments, the second terminal carboxyl group leading to the synthesis of pimelic acid is enzymatically formed by a CoA-transferase such as a glutaconate CoA-transferase classified, for example, under EC 2.8.3.12 such as from Acidaminococcus fermentans. See, for example, Buckel et al., 1981, Eur. J. Biochem., 118:315-321.
In some embodiments, the second terminal carboxyl group leading to the synthesis of pimelic acid is enzymatically formed by a reversible CoA-ligase such as a succinate-CoA ligase classified, for example, under EC 6.2.1.5 such as from Thermococcus kodakaraensis. See, for example, Shikata et al., 2007, J. Biol. Chem., 282(37):26963-26970.
Enzymes Generating the Terminal Amine Groups in the Biosynthesis of C7 Building Blocks
As depicted in FIGS. 5 and 6, terminal amine groups can be enzymatically formed using a ω-transaminase or a deacetylase.
In some embodiments, the first or second terminal amine group leading to the synthesis of 7-aminoheptanoic acid is enzymatically formed by a ω-transaminase classified, for example, under EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82 such as that obtained from Chromobacterium violaceum (Genbank Accession No. AAQ59697.1, SEQ ID NO: 13), Pseudomonas aeruginosa (Genbank Accession No. AAG08191.1, SEQ ID NO: 14), Pseudomonas syringae (Genbank Accession No. AAY39893.1, SEQ ID NO: 15), Rhodobacter sphaeroides (Genbank Accession No. ABA81135.1, SEQ ID NO: 16), Escherichia coli (Genbank Accession No. AAA57874.1, SEQ ID NO: 17), Vibrio fluvialis (Genbank Accession No. AEA39183.1, SEQ ID NO: 18), Streptomyces griseus, or Clostridium viride. Some of these ω-transaminases are diamine ω-transaminases (e.g., SEQ ID NO: 17). For example, the ω-transaminases classified, for example, under EC 2.6.1.29 or EC 2.6.1.82 may be diamine ω-transaminases.
The reversible ω-transaminase from Chromobacterium violaceum (Genbank Accession No. AAQ59697.1, SEQ ID NO: 13) has demonstrated analogous activity accepting 6-aminohexanoic acid as amino donor, thus forming the first terminal amine group in adipate semialdehyde (Kaulmann et al., Enzyme and Microbial Technology, 2007, 41, 628-637).
The reversible 4-aminobubvrate:2-oxoglutarate transaminase from Streptomyces griseus has demonstrated analogous activity for the conversion of 6-aminohexanoate to adipate semialdehyde (Yonaha et al., Eur. J. Biochem., 1985, 146:101-106).
The reversible 5-aminovalerate transaminase from Clostridium viride has demonstrated analogous activity for the conversion of 6-aminohexanoate to adipate semialdehyde (Barker et al., J. Biol. Chem., 1987, 262(19), 8994-9003).
In some embodiments, a terminal amine group leading to the synthesis of 7-aminoheptanoate or heptamethylenediamine is enzymatically formed by a diamine ω-transaminase. For example, the second terminal amino group can be enzymatically formed by a diamine ω-transaminase classified, for example, under EC 2.6.1.29 or classified, for example, under EC 2.6.1.82, such as the gene product of YgjG from E. coli (Genbank Accession No. AAA57874.1, SEQ ID NO: 17).
The gene product of ygjG accepts a broad range of diamine carbon chain length substrates, such as putrescine, cadaverine and spermidine (see, for example, Samsonova et al., BMC Microbiology, 2003, 3:2).
The diamine ω-transaminase from E. coli strain B has demonstrated activity for 1,7 diaminoheptane (Kim, The Journal of Chemistry, 1964, 239(3), 783-786).
In some embodiments, the second terminal amine group leading to the synthesis of heptamethylenediamine is enzymatically formed by a deacetylase such as an acyl-lysine deacylase classified, for example, under EC 3.5.1.17 or such as acetylputrescine deacetylase classified, for example, under EC 3.5.1.62. The acetylputrescine deacetylase from Micrococcus luteus K-11 accepts a broad range of carbon chain length substrates, such as acetylputrescine, acetylcadaverine and N8-acetylspermidine (see, for example, Suzuki et al., 1986, BBA—General Subjects, 882(1): 140-142).
Enzymes Generating the Terminal Hydroxyl Groups in the Biosynthesis of C7 Building Blocks
As depicted in FIGS. 7 and 8, a terminal hydroxyl group can be enzymatically formed using 6-hydroxyhexanoate dehydrogenase, a 5-hydroxypentanoate dehydrogenase, 4-hydroxybutyrate dehydrogenase, or an alcohol dehydrogenase.
For example, a terminal hydroxyl group leading to the synthesis of 7-hydroxyheptanoic acid can be enzymatically formed by a dehydrogenase classified, for example, under EC 1.1.1.- such as a 6-hydroxyhexanoate dehydrogenase classified, for example, under EC 1.1.1.258 (e.g., the gene from of ChnD), a 5-hydroxypentanoate dehydrogenase classified, for example, under EC 1.1.1.- such as the gene product of CpnD (see, for example, Iwaki et al., 2002, Appl. Environ. Microbiol., 68(11):5671-5684), a 5-hydroxypentanoate dehydrogenase from Clostridium viride, or a 4-hydroxybutyrate dehydrogenase such as gbd. See, FIG. 7.
In some embodiments, the second terminal hydroxyl group leading to the synthesis of 1,7 heptanediol is enzymatically formed by an alcohol dehydrogenase classified, for example, under EC 1.1.1.- (e.g., EC 1.1.1.1, EC 1.1.1.2, EC 1.1.1.21, or EC 1.1.1.184).
Biochemical Pathways
Pathway using acetyl-CoA or 2-oxo-glutarate as Central Metabolite in the Biosynthesis of C7 Backbone
In some embodiments, glutaryl-CoA is synthesized from the central metabolite, acetyl-CoA, by conversion of acetyl-CoA to acetoacetyl-CoA by a β-ketothiolase classified, for example, under EC 2.3.1.9 such as the gene product of atoB or phaA or by an acetyl-CoA carboxylase classified under, for example, EC 6.4.1.2 and an acetoacelyl-CoA synthase classified, for example, under EC 2.3.1.194; followed by conversion to 3-hydroxybutanoyl-CoA by a 3-hydroxyacyl-CoA dehydrogenase classified, for example, under EC 1.1.1.- such as EC 1.1.1.157 or EC 1.1.1.35 such as the gene product of hbd; followed by conversion to crotonyl-CoA by an enoyl-CoA reductase classified, for example, under EC 4.2.1.- (e.g., EC 4.2.1.17) such as the gene product of crt, followed by conversion to either a) glutaconyl-CoA by a glutaconyl-CoA decarboxylase classified, for example, under EC 4.1.1.70; followed by conversion to glutaryl-CoA by either (i) an enoyl-[acp] reductase classified, for example, under EC 1.3.1.9 or (ii) a trans-2-enoyl-CoA reductase classified, for example, under EC 1.3.1.44 such as the gene product of ter or tdter or (b) glutaryl-CoA by a glutaryl-CoA dehydrogenase subject to electron bifurcation from Synthrophus aciditrophicus such as the dehydrogenases of Genbank Accession Nos. (1) ABC77899.1, (2) ABC76101.1, (3) ABC76260.1, (4) ABC76949.1 or (5) ABC78863.1. See, FIG. 1.
In some embodiments, glutaryl-CoA can be synthesized from the central metabolite, 2-oxo-glutarate, by conversion of 2-oxo-glutrate to (Homo)1citrate by a homocitrate synthase classified, for example, under EC 2.3.3.14 or EC 2.3.3.13 such as the gene product of LYS20 and LYS21 from Saccharomyces cerevisiae or hcs from Thermus thermophiles; followed by conversion to iso(homo)1citrate by a homocitrate dehydratase and a homoaconitate hydratase classified, for example, under EC 4.2.1.114, EC 4.2.1.36 or EC 4.2.1.33 such as the gene product of LYS4 from Saccharomyces cerevisiae or lysT and LysU from Thermus thermophiles; followed by conversion to 2-oxoadipate by an iso(homo)ncitrate dehydrogenase classified, for example, under EC 1.1.1.85, EC 1.1.1.87 or EC 1.1.1.286 such as the gene product of LYS12 from Saccharomyces cerevisiae or hicdh from Thermus thermophiles; followed by conversion to glutarate semialdehyde by a decarboxylase classified, for example under EC 4.1.1.43, EC 4.1.1.74, EC 4.1.1.72 such as an indolepyruvale decarboxylase (e.g., GenBank Accession No. CAC48239.1), a branched-chain alpha-ketoacid decarboxylase (e.g., Genbank Accession No. AAS49166.1) or an alpha-ketoisovalerate decarboxylase (e.g., Genbank Accession No. ADA65057.1); followed by conversion to glutarate by a glutarate semialdehyde dehydrogenase classified, for example, under EC 1.2.1.20, EC 1.2.1.16, EC 1.2.1.79, EC 1.2.1.3, or EC 1.2.1.63 such as the gene product of CpnE, ChnE, or ThnG; followed by conversion to glutaryl-CoA by a glutarate:CoA ligase classified, for example, under EC 6.2.1.6 or by a CoA-transferase classified, for example, under EC 2.8.3.12. See, e.g., FIG. 1.
In some embodiments, pimeloyl-CoA can be synthesized from glutaryl-CoA produced as described above by conversion of glutaryl-CoA to 3-ketopimeloyl-CoA by a β-ketothiolase classified under EC 2.3.1.-, e.g., EC 2.3.1.174 or EC 2.3.1.16 such as the gene product of paaJ or homologs of paaJ (e.g., Genbank Accession No. ABC78517.1, AAC74479.1, or ABC78881.1) or by a β-ketoacyl-[acp] synthase classified, for example, under EC 2.3.1.41, EC 2.3.1.179, EC 2.3.1.180; followed by conversion to 3-hydroxypimeloyl-CoA by a 3-hydroxyadipyl-CoA dehydrogenase classified, for example, under EC 1.1.1.157 such as the gene product of paaH or homologs of paaH (e.g., Genbank Accession No. ABC77793.1); followed by conversion to 2(E)-heptenedioyl-CoA (also known as 2,3-dehydropimeloyl-CoA) by an enoyl-CoA hydratase such as the gene product of paaF or homologs of paaF (e.g., Genbank Accession No. ABC77794.1 or Genbank Accession No. ABC78950.1); followed by conversion to 2(E)-heptenedioate by an acyl-[acp] thioesterase classified under EC 3.1.2.-, such as the acyl-[acp] thioesterase from Lactobacillus brevis (GenBank Accession No. ABJ63754.1, SEQ ID NO: 4) or from Lactobacillus plantarum (GenBank Accession No. CCC78182.1, SEQ ID NO: 5) or CoA-transferase classified under EC 2.8.3.- such as EC 2.8.3.12 (see, e.g., Genbank Accession No. CAA57199.1 (GctA) and CAA57200.1 (GctB), SEQ ID NOs: 24 and 25, respectively), followed by conversion to 2(E)-heptenedioate methyl ester using a fatty acid O-methyltransferase classified, for example, under EC 2.1.1.15 such as the fatty acid O-methyltransferase from Mycobacterium marinum M (GenBank Accession No. ACC41782.1, SEQ ID NO: 1); Mycobacterium smegmatis (see GenBank Accession No. ABK73223.1, SEQ ID NO: 2), or Pseudomonas putida (see GenBank Accession No. CAA39234.1, SEQ ID NO: 3); followed by conversion to 2(E)-heptenedioyl-CoA methyl ester by a CoA ligase classified, for example, under EC 6.2.1.- (e.g., a butyrate-CoA ligase classified under EC 6.2.1.2 or a long-chain-fatty-acid-CoA ligase classified under EC 6.2.1.3); followed by conversion to pimeloyl-CoA methyl ester using a trans-2-enovl-CoA reductase classified, for example, under EC 1.3.1.44 such as the gene product of ter or tdter; followed by conversion to pimeloyl-CoA by a pimelyl-[acp] methyl ester esterase classified, for example, under EC 3.1.1.85 such as the gene product of bioH from E. coli. (GenBank Accession No. AAC76437.1, SEQ ID NO: 6). See, e.g., FIG. 1.
In some embodiments, pimeloyl-CoA can be synthesized from the central metabolite, 2-oxo-glutarate, by two cycles of 2-oxoacid chain elongation by conversion of 2-oxoglutrate to (Homo)1citrate by a (Homo)ncitrate synthase classified, for example, under EC 2.3.3.14 or EC 2.3.3.13 (see, e.g., AksA, Genbank Accession No. AAB98494.1); followed by conversion to iso(homo)1citrate by a (homo)ncitrate dehydratase and a (homo)naconitate hydratase classified, for example, under EC 4.2.1.114, EC 4.2.1.36 or EC 4.2.1.33 (see, e.g., AksD and AksE, Genbank Accession Nos. AAB99007.1 and AAB99277.1); followed by conversion to 2-oxoadipate by an iso(homo)ncitrate dehydrogenase classified, for example, under EC 1.1.1.85, EC 1.1.1.87 or EC 1.1.1.286 (see, e.g., AksF, Genbank Accession No. ACA28837.1); followed by conversion to (Homo)2citrate by a (Homo)ncitrate synthase classified, for example, under EC 2.3.3.14 or EC 2.3.3.13 (see, e.g., AksA, Genbank Accession No. AAB98494.1); followed by conversion to iso(homo)2citrate (also known as 1-hydroxypentane-1,2,5-tricarboxylate or threo-iso(homo)2citrate) by a (homo)ncitrate dehydratase and a (homo),aconitate hydratase classified, for example, under EC 4.2.1.114, EC 4.2.1.36 or EC 4.2.1.33 (see, e.g., Genbank Accession Nos. AAB99007.1 and AAB99277.1); followed by conversion to 2-oxo-pimelate by an iso(homo)ncitrate dehydrogenase classified under, for example, EC 1.1.1.85, EC 1.1.1.87, or EC 1.1.1.286 (see, e.g., AksF, Genbank Accession No. ACA28837.1); followed by conversion to 2-oxo-pimelate using an alcohol dehydrogenase classified under EC 1.1.1.- such as the gene product of HgdH (see Djurdjevic et al, 2011, supra) or LdhA (see Kim et al., 2005, FEBS Journal, 272, 550-561); followed by conversion to 2-hydroxypimeloyl-CoA by a CoA-transferase such as a glutaconate CoA-transferase classified, for example, under EC 2.8.3.12 (e.g., the gene product of GctAB); followed by conversion to 2(E)-heptenedioyl-CoA by a 2-hydroxyglutaryl-CoA dehydratase classified, for example, under EC 4.2.1.- such as the gene product of HgdAB in combination with its activator, the gene product of HgdC (see Djurdjevic et al, 2011, supra) or a 2-hydroxyisocaproyl-CoA dehydratase classified, for example, under EC 4.2.1.- such as the gene product of hadBC in combination with its activator, the gene product of hadI (Kim et al., 2005, supra); followed by conversion to 2(E)-heptenedioate by a CoA-transferase such as a glutaconate CoA-transferase classified, for example, under EC 2.8.3.12 (e.g., the gene product of GctAB); followed by conversion to 2(E)-heptenedioate methyl ester using a fatty acid O-methyltransferase classified, for example, under EC 2.1.1.15 such as the fatty acid O-methyltransferase from Mycobacterium marimum MA (GenBank Accession No. ACC41782.1, SEQ ID NO: 1); Mycobacterium smegmatis (see GenBank Accession No. ABK73223.1, SEQ ID NO: 2), or Pseudomonas putida (see GenBank Accession No. CAA39234.1, SEQ ID NO: 3); followed by conversion to 2(E)-heptenedioyl-CoA methyl ester by a CoA ligase classified, for example, under EC 6.2.1.- (e.g., a butyrate-CoA ligase classified under EC 6.2.1.2 or a long-chain-fatty-acid-CoA ligase classified under EC 6.2.1.3); followed by conversion to pimeloyl-CoA methyl ester using a trans-2-enoyl-CoA reductase classified, for example, under EC 1.3.1.44 such as the gene product of ter or tdter; followed by conversion to pimeloyl-CoA by a pimelyl-[acp] methyl ester esterase classified, for example, under EC 3.1.1.85 such as the gene product of bioH from E. coli. (GenBank Accession No. AAC76437.1, SEQ ID NO: 6). See, e.g., FIG. 2.
Pathway Using Succinate Semialdehyde as Central Metabolite in the Biosynthesis of C7 Backbone
In some embodiments, pimeloyl-CoA can be synthesized from (i) the central metabolite 2-oxoglutarate by conversion of 2-oxoglutarate to succinate semialdehyde by a branched-chain alpha-ketoacid decarboxylase (e.g., Genbank Accession No. AAS49166.1) classified, for example, under EC 4.1.1.72 or an alpha-ketoisovalerate decarboxylase (e.g., Genbank Accession No. ADA65057.1) classified, for example, under EC 4.1.1.74 or from (ii) the central metabolite succinyl-CoA by conversion of succinyl-CoA to succinate semialdehyde by a succinate-semialdehyde dehydrogenase classified, for example, under EC 1.2.1.76; followed by conversion to 2,4-dihydroxyhept-2-enedioate by a 4-hydroxy-2-oxoheptanedioate aldolase classified, for example, under EC 4.1.2.52 (e.g., the gene product of HpaI); followed by conversion to 2-oxohept-3-enedioate by a 2-oxo-hept-3-ene-1, 7-dioate hydratase classified, for example, under EC 4.2.1.- such as the gene product of HpaH (e.g., Genbank Accession No. AAB91474.1); followed by conversion to 2-oxopimelate by a 2-enoate reductase classified under EC 1.3.1.- such as EC 1.3.1.31 or EC 1.6.99.- such as EC 1.6.99.1 (e.g., encoded by Genbank Accession Nos. BAA12619.1, AAN66878.1, AAA98815.1, AGP69310.1, CAA37666.1, ABY93685.1, or AAB38683.1); followed by conversion to 2-hydroxypimelate by a 2-hydroxyglutarate dehydrogenase classified, for example under EC 1.1.1.- such as EC 1.1.1.337 (e.g., the gene product of HgdH or IdhA); followed by conversion to 2-hydroxypimeloyl-CoA by a CoA-transferase such as a glutaconate CoA-transferase classified, for example, under EC 2.8.3.12 (e.g., the gene product of GctAB); followed by conversion to 2(E)-heptenedioyl-CoA by a 2-hydroxyglutaryl-CoA dehydratase classified, for example, under EC 4.2.1.- such as the gene product of HgdAB in combination with its activator, the gene product of HgdC (see, Djurdjevic et al, 2011, supra) or a 2-hydroxyisocaproyl-CoA dehydratase classified, for example, under EC 4.2.1.- such as the gene product of hadBC in combination with its activator, the gene product of hadI (Kim et al., 2005, supra); followed by conversion to 2(E)-heptenedioate by a CoA-transferase such as a glutaconate CoA-transferase classified, for example, under EC 2.8.3.12 (e.g., the gene product of GctAB); followed by conversion to 2(E)-heptenedioate methyl ester using a fatty acid O-methyltransferase classified, for example, under EC 2.1.1.15 such as the fatty acid O-methyltransferase from Mycobacterium marinum (GenBank Accession No. ACC41782.1. SEQ ID NO: 1); Mycobacterium smegmatis (see GenBank Accession No. ABK73223.1, SEQ ID NO: 2), or Pseudomonas putida (see GenBank Accession No. CAA39234.1, SEQ ID NO: 3); followed by conversion to 2(E)-heptenedioyl-CoA methyl ester by a CoA ligase classified, for example, under EC 6.2.1.- such as a butyrate-CoA ligase classified, for example, under EC 6.2.1.2 or a long-chain-fatty-acid-CoA ligase classified, for example, under EC 6.2.1.3 (e.g. Genbank Accession No. CAA50321.1 or CAJ95550.1); followed by conversion to pimeloyl-CoA methyl ester using a trans-2-enoyl-CoA reductase classified, for example, under EC 1.3.1.44 such as the gene product of ter (e.g., Genbank Accession No. AAW66853.1) or tdter (Genbank Accessio No. AAS11092.1); followed by conversion to pimeloyl-CoA by a pimelyl-[acp] methyl ester esterase classified, for example, under EC 3.1.1.85 such as the gene product of bioH from E. coli. (GenBank Accession No. AAC76437.1, SEQ ID NO: 6). See, e.g., FIG. 3.
Pathways Using Pimeloyl-CoA or Pimelate Semialdehyde as Central Precursors to Pimelate
In some embodiments, pimelic acid is synthesized from the central precursor pimeloyl-CoA by conversion of pimeloyl-CoA to pimelate semialdehyde by an acetylating aldehyde dehydrogenase classified, for example, under EC 1.2.1.10 such as the gene product of PduB or PduP (see, for example, Lan et al., 2013, Energy Environ. Sci., 6:2672-2681); followed by conversion to pimelic acid by a 7-oxoheptanoate dehydrogenase classified, for example, under EC 1.2.1.- such as the gene product of ThnG, a 6-oxohexanoate dehydrogenase classified, for example, under EC 1.2.1.63 such as the gene product of ChnE, a 5-oxopentanoate dehydrogenase classified, for example, under EC 1.2.1.- such as the gene product of CpnE, or an aldehyde dehydrogenase (classified, for example, under EC 1.2.1.3). See, FIG. 4.
In some embodiments, pimelic acid is synthesized from the central precursor pimeloyl-CoA by conversion of pimeloyl-CoA to pimelate by a thioesterase classified, for example, under EC 3.1.2.- such as the gene products of YciA, tesB (Genbank Accession No. AAA24665.1, SEQ ID NO: 21), Acot13, an acyl-[acp] thioesterase from Lactobacillus brevis (GenBank Accession No. ABJ63754.1, SEQ ID NO: 4), or an acyl-[acp] thioesterase from Lactobacillus plantarum (GenBank Accession No. CCC78182.1, SEQ ID NO: 5). See, FIG. 4.
In some embodiments, pimelate is synthesized from the central precursor pimeloyl-CoA by conversion of pimeloyl-CoA to pimelate by a CoA-transferase such as a glutaconate CoA-transferase classified, for example, under EC 2.8.3.12. See, FIG. 4.
In some embodiments, pimelate is synthesized from the central precursor pimeloyl-CoA by conversion of pimeloyl-CoA to pimelate by a reversible CoA-ligase such as a reversible succinate CoA-ligase classified, for example, under EC 6.2.1.5. See, FIG. 4.
Pathways Using Pimeloyl-CoA or Pimelate Semialdehyde as Central Precursor to 7-aminoheptanoate
In some embodiments, 7-aminoheptanoate is synthesized from the central precursor pimeloyl-CoA by conversion of pimeloyl-CoA to pimelate semialdehyde by an acetylating aldehyde dehydrogenase classified, for example, EC 1.2.1.10, such as the gene product of PduB or PduP; followed by conversion of pimelate semialdehyde to 7-aminoheptanoate by a ω-transaminase classified, for example, under EC 2.6.1.- such as EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82 such as from a Chromobacterium violaceum (see Genbank Accession No. AAQ59697.1, SEQ ID NO: 13), a Pseudomonas syringae (see Genbank Accession No. AAY39893.1, SEQ ID NO: 15), a Rhodobacter sphaeroides (see Genbank Accession No. ABA81135.1, SEQ ID NO: 16), or a Vibrio fluvialis (see Genbank Accession No. AEA39183.1, SEQ ID NO: 18). See, FIG. 5.
In some embodiments, 7-aminoheptanoate is synthesized from the central precursor pimelate by conversion of pimelate to pimelate semialdehyde by a carboxylate reductase classified, for example, under EC 1.2.99.6 such as from Segniliparus rugosus (Genbank Accession No. EFV11917.1, SEQ ID NO: 9) or Segniliparus rotundus (Genbank Accession No. ADG98140.1, SEQ ID NO: 12), in combination with a phosphopantetheine transferase enhancer (e.g., encoded by a sfp (Genbank Accession No. CAA44858.1, SEQ ID NO: 19) gene from Bacillus subtilis or npt (Genbank Accession No. ABI83656.1, SEQ ID NO: 20) gene from Nocardia), or the gene products of GriC and GriD from Streptomyces griseus (Suzuki et al., J. Antibiot., 2007, 60(6), 380-387); followed by conversion of pimelate semialdehyde to 7-aminoheptanoate by a ω-transaminase classified, for example, under EC 2.6.1.- such as EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.48, EC 2.6.1.29, EC 2.6.1.82 such as from a Chromobacterium violaceum (see Genbank Accession No. AAQ59697.1, SEQ ID NO: 13), a Pseudomonas syringae (see Genbank Accession No. AAY39893.1, SEQ ID NO: 15), a Rhodobacter sphaeroides (see Genbank Accession No. ABA81135.1, SEQ ID NO: 16), or a Vibrio fluvialis (see Genbank Accession No. AEA39183.1, SEQ ID NO: 18). See, FIG. 5.
Pathway Using 7-Aminoheptanoate, 7-Hydroxyheptanoate or Pimelate Semialdehyde as Central Precursor to Heptamethylenediamine
In some embodiments, heptamethylenediamine is synthesized from the central precursor 7-aminoheptanoate by conversion of 7-aminoheptanoate to 7-aminoheptanal by a carboxylate reductase classified, for example, under EC 1.2.99.6 such as the gene product of car (see above) in combination with a phosphopantetheine transferase enhancer (e.g., encoded by a sfp (Genbank Accession No. CAA44858.1, SEQ ID NO: 19) gene from Bacillus subtilis or npt (Genbank Accession No. ABI83656.1, SEQ ID NO: 20) gene from Nocardia) or the gene product of GriC & GriD (Suzuki et al., J. Antibiot., 2007, 60(6), 380-387); followed by conversion of 7-aminoheptanal to heptamethylenediamine by a ω-transaminase classified, for example, under EC 2.6.1.-such as 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82 such as from a Chromobacterium violaceum (see Genbank Accession No. AAQ59697.1, SEQ ID NO: 13), a Pseudomonas aeruginosa (see Genbank Accession No. AAG08191.1, SEQ ID NO: 14), a Pseudomonas syringae (see Genbank Accession No. AAY39893.1, SEQ ID NO: 15), a Rhodobacter sphaeroides (see Genbank Accession No. ABA81135.1, SEQ ID NO: 16), an Escherichia coli (see Genbank Accession No. AAA57874.1, SEQ ID NO: 17), or a Vibrio fluvialis (see Genbank Accession No. AEA39183.1, SEQ ID NO: 18). See FIG. 6.
The carboxylate reductase encoded by the gene product of car and the phosphopantetheine transferase enhancer npt or sfp has broad substrate specificity, including terminal difunctional C4 and C5 carboxylic acids (Venkitasubramanian et al., Enzyme and Microbial Technology, 2008, 42, 130-137).
In some embodiments, heptamethylenediamine is synthesized from the central precursor 7-hydroxyheptanoate (which can be produced as described in FIG. 7), by conversion of 7-hydroxyheptanoate to 7-hydroxyheptanal by a carboxylate reductase classified, for example, under EC 1.2.99.6 such as from a Mycobacterium marinum (see Genbank Accession No. ACC40567.1, SEQ ID NO: 7), a Mycobacterium smegmatis (see Genbank Accession No. ABK71854.1, SEQ ID NO: 8), a Segniliparus rugosus (see Genbank Accession No. EFV1917.1, SEQ ID NO: 9), a Mycobacterium smegmatis (see Genbank Accession No. ABK75684.1, SEQ ID NO: 10), a Mycobacterium massiliense (see Genbank Accession No. EIV11143.1, SEQ ID NO: 11), or a Segniliparus rotundus (see Genbank Accession No. ADG98140.1, SEQ ID NO: 12), in combination with a phosphopantetheine transferase enhancer (e.g., encoded by a sfp (Genbank Accession No. CAA44858.1, SEQ ID NO: 19) gene from Bacillus subtilis or npt (Genbank Accession No. ABI83656.1, SEQ ID NO: 20) gene from Nocardia), or the gene product of GriC & GriD (Suzuki et al., J. Antibiot., 2007, 60(6), 380-387); followed by conversion of 7-aminoheptanal to 7-aminoheptanol by a ω-transaminase classified, for example, under EC 2.6.1.- such as EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82 from a Chromobacterium violaceum (see Genbank Accession No. AAQ59697.1, SEQ ID NO: 13), a Pseudomonas syringae (see Genbank Accession No. AAY39893.1, SEQ ID NO: 15), or a Rhodobacter sphaeroides (see Genbank Accession No. ABA81135.1, SEQ ID NO: 16); followed by conversion to 7-aminoheptanal by an alcohol dehydrogenase classified, for example, under EC 1.1.1.- (e.g., EC 1.1.1.1, EC 1.1.1.2, EC 1.1.1.21, or EC 1.1.1.184) such as the gene product of YMR318C (classified, for example, under EC 1.1.1.2, see Genbank Accession No. CAA90836.1) (classified, for example, under EC 1.1.1.2, see Genbank Accession No. CAA90836.1) or YqhD (from E. coli, GenBank Accession No. AAA69178.1) (Liu et al., Microbiology, 2009, 155, 2078-2085; Larroy et al., 2002, Biochem J., 361(Pt 1), 163-172; Jarboe, 2011, Appl. Microbiol. Biotechnol., 89(2), 249-257) or the protein having GenBank Accession No. CAA81612.1 (from Geobacillus stearothermophilus); followed by conversion to heptamethylenediamine by a ω-transaminase classified, for example, under EC 2.6.1.-such as 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82 such as from a Chromobacterium violaceum (see Genbank Accession No. AAQ59697.1, SEQ ID NO: 13), a Pseudomonas aeruginosa (see Genbank Accession No. AAG08191.1, SEQ ID NO: 14), a Pseudomonas syringae (see Genbank Accession No. AAY39893.1, SEQ ID NO: 15), a Rhodobacter sphaeroides (see Genbank Accession No. ABA81135.1, SEQ ID NO: 16), an Escherichia coli (see Genbank Accession No. AAA57874.1, SEQ ID NO: 17), or a Vibrio fluvialis (see Genbank Accession No. AEA39183.1, SEQ ID NO: 18). See FIG. 6.
In some embodiments, heptamethylenediamine is synthesized from the central precursor 7-aminoheptanoate by conversion of 7-aminoheptanoate to N7-acetyl-7-aminoheptanoate by a N-acetyltrasferase such as a lysine N-acetyltransferase classified, for example, under EC 2.3.1.32; followed by conversion to N7-acetyl-7-aminoheptanal by a carboxylate reductase classified, for example, under EC 1.2.99.6 such as from a Mycobacterium smegmatis (see Genbank Accession No. ABK71854.1, SEQ ID NO: 8), a Mycobacterium massiliense (see Genbank Accession No. EIV1143.1, SEQ ID NO: 11), or a Segniliparus rotundus (see Genbank Accession No. ADG98140.1, SEQ ID NO: 12), in combination with a phosphopantetheine transferase enhancer (e.g., encoded by a sfp (Genbank Accession No. CAA44858.1, SEQ ID NO: 19) gene from Bacillus subtilis or npt (Genbank Accession No. ABI83656.1, SEQ ID NO: 20) gene from Nocardia), or the gene product of GriC & GriD (Suzuki et al., J. Antibiot., 2007, 60(6), 380-387); followed by conversion to N7-acetyl-1,7-diaminoheptane by a ω-transaminase classified, for example, under EC 2.6.1.- such as EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, EC 2.6.1.46, or EC 2.6.1.82 such as from a Chromobacterium violaceum (see Genbank Accession No. AAQ59697.1, SEQ ID NO: 13), a Pseudomonas aeruginosa (see Genbank Accession No. AAG08191.1, SEQ ID NO: 14), a Pseudomonas syringae (see Genbank Accession No. AAY39893.1, SEQ ID NO: 15), a Rhodobacter sphaeroides (see Genbank Accession No. ABA81135.1, SEQ ID NO: 16), an Escherichia coli (see Genbank Accession No. AAA57874.1, SEQ ID NO: 17), or a Vibrio fluvialis (see Genbank Accession No. AEA39183.1, SEQ ID NO: 18); followed by conversion to heptamethylenediamine by an acetylputrescine deacetylase classified, for example, under EC 3.5.1.62 or EC 3.5.1.17. See, FIG. 6.
In some embodiments, heptamethylenediamine is synthesized from the central precursor pimelate semialdehyde by conversion of pimelate semialdehyde to heptanedial by a carboxylate reductase classified, for example, under EC 1.2.99.6 such as from a Segniliparus rotundus (see Genbank Accession No. ADG98140.1, SEQ ID NO: 12), in combination with a phosphopantetheine transferase enhancer (e.g., encoded by a sfp (Genbank Accession No. CAA44858.1, SEQ ID NO: 19) gene from Bacillus subtilis or npt (Genbank Accession No. ABI83656.1, SEQ ID NO: 20) gene from Nocardia), or the gene product of GriC & GriD (Suzuki et al., J. Antibiot., 2007, 60(6), 380-387); followed by conversion to 7-aminoheptanal by a ω-transaminase classified, for example, under EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82; followed by conversion to heptamethylenediamine by a ω-transaminase classified, for example, under EC 2.6.1.- such as 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82 such as from a Chromobacterium violaceum (see Genbank Accession No. AAQ59697.1, SEQ ID NO: 13), a Pseudomonas aeruginosa (see Genbank Accession No. AAG08191.1, SEQ ID NO: 14), a Pseudomonas syringae (see Genbank Accession No. AAY39893.1, SEQ ID NO: 15), a Rhodobacter sphaeroides (see Genbank Accession No. ABA81135.1, SEQ ID NO: 16), an Escherichia coli (see Genbank Accession No. AAA57874.1, SEQ ID NO: 17), or a Vibrio fluvialis (see Genbank Accession No. AEA39183.1, SEQ ID NO: 18). See FIG. 6.
Pathways Using Pimelate or Pimelate Semialdehyde as Central Precursor to 7-Hydroxyheptanoic Acid and 1,7-Heptanediol
In some embodiments, 7-hydroxyheptanoate is synthesized from the central precursor pimelate by conversion of pimelate to pimelate semialdehyde by a carboxylate reductase classified, for example, under EC 1.2.99.6 such as from Segniliparus rugosus (Genbank Accession No. EFV11917.1, SEQ ID NO: 9) or Segniliparus rotundus (Genbank Accession No. ADG98140.1, SEQ ID NO: 12), in combination with a phosphopantetheine transferase enhancer (e.g., encoded by a sfp (Genbank Accession No. CAA44858.1, SEQ ID NO: 19) gene from Bacillus subtilis or npt (Genbank Accession No. ABI83656.1, SEQ ID NO: 20) gene from Nocardia), or the gene products of GriC and GriD from Streptomyces griseus; followed by conversion to 7-hydroxyheptanoate by an alcohol dehydrogenase classified, for example, under EC 1.1.1.- such as a 6-hydroxyhexanoate dehydrogenase classified, for example, under EC 1.1.1.258 (e.g., the gene from of ChnD), a 5-hydroxypentanoate dehydrogenase classified, for example, under EC 1.1.1.- such as the gene product of CpnD (see, for example, Iwaki et al., 2002, Appl. Environ. Microbiol., 68(11):5671-5684), a 5-hydroxypentanoate dehydrogenase from Clostridium viride, or a 4-hydroxybutyrate dehydrogenase such as gbd. See, FIG. 7.
In some embodiments, 7-hydroxyheptanoate is synthesized from the central precursor pimeloyl-CoA by conversion of pimeloyl-CoA to pimelate semialdehyde by an acetylating aldehyde dehydrogenase classified, for example, under EC 1.2.1.10 such as the gene product of PduB or PduP; followed by conversion to 7-hydroxyheptanoate by an alcohol dehydrogenase classified, for example, under EC 1.1.1.- such as a 6-hydroxyhexanoate dehydrogenase classified, for example, under EC 1.1.1.258 (e.g., the gene from of ChnD)), a 5-hydroxypentanoate dehydrogenase classified, for example, under EC 1.1.1.- such as the gene product of CpnD, a 5-hydroxypentanoate dehydrogenase from Clostridium viride, or a 4-hydroxybutyrate dehydrogenase such as gbd. See, also FIG. 7.
In some embodiments, 1,7 heptanediol is synthesized from the central precursor 7-hydroxyheptanoate by conversion of 7-hydroxyheptanoate to 7-hydroxyheptanal by a carboxylate reductase classified, for example, under EC 1.2.99.6 such as from a Mycobacterium marinum (see Genbank Accession No. ACC40567.1, SEQ ID NO: 7), a Mycobacterium smegmatis (see Genbank Accession No. ABK71854.1, SEQ ID NO: 8), a Segniliparus rugosus (see Genbank Accession No. EFV11917.1, SEQ ID NO: 9), a Mycobacterium smegmatis (see Genbank Accession No. ABK75684.1, SEQ ID NO: 10), a Mycobacterium massiliense (see Genbank Accession No. EIV11143.1, SEQ ID NO: 11), or a Segniliparus rotundus (see Genbank Accession No. ADG98140.1, SEQ ID NO: 12), in combination with a phosphopantetheine transferase enhancer (e.g., encoded by a sfp (Genbank Accession No. CAA44858.1, SEQ ID NO: 19) gene from Bacillus subtilis or npt (Genbank Accession No. ABI83656.1, SEQ ID NO: 20) gene from Nocardia). or the gene product of GriC & Gril) (Suzuki et al., J. Antibiot., 2007, 60(6), 380-387); followed by conversion of 7-hydroxyheptanal to 1,7 heptanediol by an alcohol dehydrogenase classified, for example, under EC 1.1.1.- (e.g., EC 1.1.1.1, EC 1.1.1.2, EC 1.1.1.21, or EC 1.1.1.184) such as the gene product of YMR318C (classified, for example, under EC 1.1.1.2, see Genbank Accession No. CAA90836.1) or YqhD (from E. coli, GenBank Accession No. AAA69178.1) (Liu et al., Microbiology, 2009, 155, 2078-2085; Larroy et al., 2002, Biochem J., 361(Pt 1), 163-172; Jarboe, 2011, Appl. Microbiol. Biotechnol., 89(2), 249-257) or the protein having GenBank Accession No. CAA81612.1 (from Geobacillus stearothermophilus). See, FIG. 8.
Cultivation Strategy
In some embodiments, the cultivation strategy entails achieving an aerobic, anaerobic, micro-aerobic, or mixed oxygen/denitrification cultivation condition. Enzymes characterized in vitro as being oxygen sensitive require a micro-aerobic cultivation strategy maintaining a very low dissolved oxygen concentration (See, for example, Chayabatra & Lu-Kwang, Appl. Environ. Microbiol., 2000, 66(2), 493-498; Wilson and Bouwer, 1997, Journal of Industrial Microbiology and Biotechnology, 18(2-3), 116-130).
In some embodiments, the cultivation strategy entails nutrient limitation such as nitrogen, phosphate or oxygen limitation.
In some embodiments, a final electron acceptor other than oxygen such as nitrates can be utilized.
In some embodiments, a cell retention strategy using, for example, ceramic membranes can be employed to achieve and maintain a high cell density during either fed-batch or continuous fermentation.
In some embodiments, the principal carbon source fed to the fermentation in the synthesis of one or more C7 building blocks can derive from biological or non-biological feedstocks.
In some embodiments, the biological feedstock can be, can include, or can derive from, monosaccharides, disaccharides, lignocellulose, hemicellulose, cellulose, lignin, levulinic acid and formic acid, triglycerides, glycerol, fatty acids, agricultural waste, condensed distillers' solubles, or municipal waste.
The efficient catabolism of crude glycerol stemming from the production of biodiesel has been demonstrated in several microorganisms such as Escherichia coli, Cupriavidus necator, Pseudomonas oleamwrans, Pseudomonas putida and Yarrowia lipolytica (Lee et al., Appl. Biochem. Biotechnol., 2012, 166, 1801-1813; Yang et al., Biotechnology for Biofuels, 2012, 5: 13; Meijnen et al., Appl. Microbiol. Biotechnol., 2011, 90, 885-893).
The efficient catabolism of lignocellulosic-derived levulinic acid has been demonstrated in several organisms such as Cupriavidus necator and Pseudomonas putida in the synthesis of 3-hydroxyvalerate via the precursor propanoyl-CoA (Jaremko and Yu, Journal of Biotechnology, 2011, 155, 2011, 293-298; Martin and Prather, Journal of Biotechnology, 2009, 139, 61-67).
The efficient catabolism of lignin-derived aromatic compounds such as benzoate analogues has been demonstrated in several microorganisms such as Pseudomonas putida, Cupriavidus necator (Bugg et al., Current Opinion in Biotechnology, 2011, 22, 394-400; Pérez-Pantoja et al., FEMS Microbiol. Rev., 2008, 32, 736-794).
The efficient utilization of agricultural waste, such as olive mill waste water has been demonstrated in several microorganisms, including Yarrowia lipolytica (Papanikolaou et al., Bioresour. Technol., 2008, 99(7), 2419-2428).
The efficient utilization of fermentable sugars such as monosaccharides and disaccharides derived from cellulosic, hemicellulosic, cane and beet molasses, cassava, corn and other agricultural sources has been demonstrated for several microorganism such as Escherichia coli, Corynebacterium glutamicum and Lactobacillus delbrueckii and Lactococcus lactis (see, e.g., Hermann et al, Journal of Biotechnology, 2003, 104, 155-172; Wee et al., Food Technol. Biotechnol., 2006, 44(2), 163-172; Ohashi et al., Journal of Bioscience and Bioengineering, 1999, 87(5), 647-654).
The efficient utilization of furfural, derived from a variety of agricultural lignocellulosic sources, has been demonstrated for Cupriavidus necator (Li et al., Biodegradation, 2011, 22, 1215-1225).
In some embodiments, the non-biological feedstock can be or can derive from natural gas, syngas, CO2/H2, methanol, ethanol, benzoic acid, non-volatile residue (NVR), a caustic wash waste stream from cyclohexane oxidation processes, or terephthalic acid/isophthalic acid mixture waste streams.
The efficient catabolism of methanol has been demonstrated for the methylotrophic yeast Pichia pastoris. 
The efficient catabolism of ethanol has been demonstrated for Clostridium kluyveri (Seedorf et al., Proc. Natl. Acad. Sci. USA, 2008, 105(6) 2128-2133).
The efficient catabolism of CO2 and H2, which may be derived from natural gas and other chemical and petrochemical sources, has been demonstrated for Cupriavidus necator (Prybylski et al., Energy, Sustainability and Society, 2012, 2:11).
The efficient catabolism of syngas has been demonstrated for numerous microorganisms, such as Clostridium jungdahlii and Clostridium autoethanogenum (Köpke et al., Applied and Environmental Microbiology, 2011, 77(15), 5467-5475).
The efficient catabolism of the non-volatile residue waste stream from cyclohexane processes has been demonstrated for numerous microorganisms, such as Delftia acidovorans and Cupriavidus necalor (Ramsay et al., Applied and Environmental Microbiology, 1986, 52(1), 152-156). In some embodiments, the host microorganism is a prokaryote. For example, the prokaryote can be a bacterium from the genus Escherichia such as Escherichia coli; from the genus Clostridia such as Clostridium ljungdahlii, Clostridium autoethanogenum or Clostridium kluyveri; from the genus Corynebacteria such as Corynebacterium glutamicum; from the genus Cupriavidus such as Cupriavidus necator or Cupriavidus metallidurans; from the genus Pseudomonas such as Pseudomonas fluorescens, Pseudomonas putida or Pseudomonas oleavorans; from the genus Delftia such as Delftia acidovorans; from the genus Bacillus such as Bacillus subtillis; from the genus Lactobacillus such as Lactobacillus delbrueckii; or from the genus Lactococcus such as Lactococcus lactis. Such prokaryotes also can be a source of genes to construct recombinant host cells described herein that are capable of producing one or more C7 building blocks.
In some embodiments, the host microorganism is a eukaryote. For example, the eukaryote can be a filamentous fungus, e.g., one from the genus Aspergillus such as Aspergillus niger. Alternatively, the eukaryote can be a yeast, e.g., one from the genus Saccharomyces such as Saccharomyces cerevisiae; from the genus Pichia such as Pichia pastoris; or from the genus Yarrowia such as Yarrowia lipolytica; from the genus Issatchenkia such as Issathenkia orientalis; from the genus Debaryomyces such as Debaryomyces hansenii; from the genus Arxula such as Arxula adenoinivorans; or from the genus Kluvveromyces such as Kluyveromyces lactis. Such eukaryotes also can be a source of genes to construct recombinant host cells described herein that are capable of producing one or more C7 building blocks.
Metabolic Engineering
The present document provides methods involving less than all the steps described for all the above pathways. Such methods can involve, for example, one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve or more of such steps. Where less than all the steps are included in such a method, the first, and in some embodiments the only, step can be any one of the steps listed.
Furthermore, recombinant hosts described herein can include any combination of the above enzymes such that one or more of the steps, e.g., one, two, three, four, five, six, seven, eight, nine, ten, or more of such steps, can be performed within a recombinant host. This document provides host cells of any of the genera and species listed and genetically engineered to express one or more (e.g., two, three, four, five, six, seven, eight, nine, 10, 11, 12 or more) recombinant forms of any of the enzymes recited in the document. Thus, for example, the host cells can contain exogenous nucleic acids encoding enzymes catalyzing one or more of the steps of any of the pathways described herein.
In addition, this document recognizes that where enzymes have been described as accepting CoA-activated substrates, analogous enzyme activities associated with [acp]-bound substrates exist that are not necessarily in the same enzyme class.
Also, this document recognizes that where enzymes have been described accepting (R)-enantiomers of substrate, analogous enzyme activities associated with (S)-enantiomer substrates exist that are not necessarily in the same enzyme class.
This document also recognizes that where an enzyme is shown to accept a particular co-factor, such as NADPH, or a co-substrate, such as acetyl-CoA, many enzymes are promiscuous in terms of accepting a number of different co-factors or co-substrates in catalyzing a particular enzyme activity. Also, this document recognizes that where enzymes have high specificity for e.g., a particular co-factor such as NADH, an enzyme with similar or identical activity that has high specificity for the co-factor NADPH may be in a different enzyme class.
In some embodiments, the enzymes in the pathways outlined herein are the result of enzyme engineering via non-direct or rational enzyme design approaches with aims of improving activity, improving specificity, reducing feedback inhibition, reducing repression, improving enzyme solubility, changing stereo-specificity, or changing co-factor specificity.
In some embodiments, the enzymes in the pathways outlined herein can be gene dosed (i.e., overexpressed by having a plurality of copies of the gene in the host organism), into the resulting genetically modified organism via episomal or chromosomal integration approaches.
In some embodiments, genome-scale system biology techniques such as Flux Balance Analysis can be utilized to devise genome scale attenuation or knockout strategies for directing carbon flux to a C7 building block.
Attenuation strategies include, but are not limited to; the use of transposons, homologous recombination (double cross-over approach), mutagenesis, enzyme inhibitors and RNA interference (RNAi).
In some embodiments, fluxomic, metabolomic and transcriptomal data can be utilized to inform or support genome-scale system biology techniques, thereby devising genome scale attenuation or knockout strategies in directing carbon flux to a C7 building block.
In some embodiments, the host microorganism's tolerance to high concentrations of a C7 building block can be improved through continuous cultivation in a selective environment.
In some embodiments (see, e.g., FIGS. 1 to 3), the host microorganism's endogenous biochemical network can be attenuated or augmented (1) to ensure the intracellular availability of 2-oxo-glutarate and acetyl-CoA; (2) to create an NADPH imbalance that may be balanced via the formation of a C7 building block; (3) to prevent degradation of central metabolites or central precursors leading to and including C7 building blocks; and/or (4) to ensure efficient efflux from the cell.
In some embodiments requiring the intracellular availability of 2-oxo-glutarate, a PEP carboxykinase or PEP carboxylase can be overexpressed in the host to generate anaplerotic carbon flux into the Krebs cycle towards 2-oxo-glutarate (Schwartz et al., 2009, Proteomics, 9, 5132-5142).
In some embodiments requiring the intracellular availability of 2-oxo-glutarate, a pyruvate carboxylase can be overexpressed in the host to generated anaplerotic carbon flux into the Krebs cycle towards 2-oxoglutarate (Schwartz et al., 2009, Proteomics, 9, 5132-5142).
In some embodiments requiring the intracellular availability of 2-oxo-glutarate, a PEP synthase can be overexpressed in the host to enhance the flux from pyruvate to PEP, thus increasing the carbon flux into the Krebs cycle via PEP carboxykinase or PEP carboxylase (Schwartz et al., 2009, Proteomics, 9, 5132-5142).
In some embodiments requiring the intracellular availability of 2-oxoglutarate for C6 building block synthesis, anaplerotic reactions enzymes such asphosphoenolpyruvate carboxylase (e.g., the gene product of pck), phosphoenolpyruvate carboxykinase (e.g., the gene product ofppc), the malic enzyme (e.g., the gene product of sfcA) and/or pyruvate carboxylase are overexpressed in the host organisms (Song and Lee, 2006, Enzyme Micr. Technol., 39, 352-361).
In some embodiments requiring intracellular availability of acetyl-CoA, endogenous enzymes catalyzing the hydrolysis of acetyl-CoA such as short-chain length thioesterases (e.g., an acetyl-CoA thioesterase) can be attenuated in the host organism.
In some embodiments requiring condensation of acetyl-CoA for C7 building block synthesis, one or more endogenous β-ketothiolases catalyzing the condensation of only acetyl-CoA to acetoacetyl-CoA such as the endogenous gene products of AtoB or phaA can be attenuated.
In some embodiments requiring the intracellular availability of acetyl-CoA, an endogenous phosphotransacetylase generating acetate such as pta can be attenuated (Shen et al., Appl. Environ. Microbiol., 2011, 77(9):2905-2915).
In some embodiments requiring the intracellular availability of acetyl-CoA, an endogenous gene in an acetate synthesis pathway encoding an acetate kinase, such as ack, can be attenuated.
In some embodiments requiring the intracellular availability of acetyl-CoA and NADH for C7 building block synthesis, an endogenous gene encoding an enzyme that catalyzes the degradation of pyruvate to lactate such as a lactate dehydrogenase encoded by ldhA can be attenuated (Shen et al., 2011, supra).
In some embodiments requiring the intracellular availability of Krebs cycle intermediates for C6 building block synthesis, 2-oxogltarate dehydrogenase is attenuated in one or more of its subunits.
In some embodiments requiring intracellular availability of Krebs cycle intermediates for C6 building block synthesis, the regulator of 2-oxoglutarate dehydrogenase is overexpressed by induction in the host microorganism.
In some embodiments requiring the intracellular availability of acetyl-CoA and NADH for C7 building block synthesis, endogenous genes encoding enzymes, such as menaquinol-fumarate oxidoreductase, that catalyze the degradation of phophoenolpyruvate to succinate such as frdBC can be attenuated (see, e.g., Shen et al., 2011, supra).
In some embodiments requiring the intracellular availability of acetyl-CoA and NADH for C7 building block synthesis, an endogenous gene encoding an enzyme that catalyzes the degradation of acetyl-CoA to ethanol such as the alcohol dehydrogenase encoded by adhE can be attenuated (Shen et al., 2011, supra).
In some embodiments where the host microorganism uses the lysine biosynthesis pathway via meso-2,6-diaminopimelate, the genes encoding the synthesis of 2-oxoadipate from 2-oxoglutarate are gene dosed into the host.
In some embodiments where the host microorganism uses the lysine biosynthesis pathway via 2-oxoadipate, the genes encoding the synthesis of lysine via meso-2,6-diaminopimelate are gene dosed into the host.
In some embodiments, an endogenous gene encoding an enzyme that catalyzes the degradation of pyruvate to ethanol such as pyruvate decarboxylase is attenuated.
In some embodiments, where pathways require excess NADPH or NADH co-factor for C7 building block synthesis, an endogenous transhydrogenase such as one classified under EC 1.6.1.1, EC 1.6.1.2, or EC 1.6.1.3, dissipating the co-factor imbalance can be attenuated.
In some embodiments, where pathways require excess NADPH co-factor for C7 building block synthesis, an exogenous transhydrogenase such as one classified under EC 1.6.1.1, EC 1.6.1.2 or EC 1.6.1.3, converting NADH to NADPH can be overexpressed.
In some embodiments using hosts that naturally accumulate polyhydroxyalkanoates, an endogenous gene encoding a polyhydroxyalkanoate synthase enzyme can be attenuated in the host strain.
In some embodiments using hosts that naturally accumulate lipid bodies, the genes encoding enzymes involved with lipid body synthesis are attenuated.
In some embodiments requiring the intracellular availability of acetyl-CoA for C7 building block synthesis, a recombinant acetyl-CoA synthetase such as the gene product of acs can be overexpressed in the microorganism (Satoh et al., J. Bioscience and Bioengineering, 2003, 95(4):335-341).
In some embodiments, an L-alanine dehydrogenase can be overexpressed in the host to regenerate L-alanine from pyruvate as amino donor for ω-transaminase reactions.
In some embodiments, a NADH-specific L-glutamate dehydrogenase can be overexpressed in the host to regenerate L-glutamate from 2-oxo-glutarate as amino donor for ω-transaminase reactions.
In some embodiments, enzymes such as pimeloyl-CoA dehydrogenase classified under, for example, EC 1.3.1.62; an acyl-CoA dehydrogenase classified under, for example, EC 1.3.8.7 or EC 1.3.8.1; and/or a glutaryl-CoA dehydrogenase classified under, for example, EC 1.3.8.6 that degrade central metabolites and central precursors leading to and including C7 building blocks can be attenuated.
In some embodiments, endogenous enzymes activating C7 building blocks via Coenzyme A esterification such as CoA-ligases such as pimeloyl-CoA synthetase classified under, for example, EC 6.2.1.14 can be attenuated.
In some embodiments, carbon flux can be directed into the pentose phosphate cycle to increase the supply of NADPH by attenuating an endogenous glucose-6-phosphate isomerase (EC 5.3.1.9).
In some embodiments, carbon flux can be redirected into the pentose phosphate cycle to increase the supply of NADPH by overexpression a 6-phosphogluconate dehydrogenase and/or a transketolase (Lee et al., 2003, Biotechnology Progress, 19(5), 1444-1449).
In some embodiments, where pathways require excess NADPH co-factor in the synthesis of a C7 building block, a gene such as UdhA encoding a puridine nucleotide transhydrogenase can be overexpressed in the host organisms (Brigham et al., Advanced Biofuels and Bioproducts, 2012, Chapter 39, 1065-1090).
In some embodiments, where pathways require excess NADPH co-factor in the synthesis of a C7 Building Block, a recombinant glyceraldehyde-3-phosphate-dehydrogenase gene such as GapN can be overexpressed in the host organisms (Brigham et al., 2012, supra).
In some embodiments, where pathways require excess NADPH co-factor in the synthesis of a C7 building block, a recombinant malic enzyme gene such as maeA or maeB can be overexpressed in the host organisms (Brigham et al., 2012, supra).
In some embodiments, where pathways require excess NADPH co-factor in the synthesis of a C7 building block, a recombinant glucose-6-phosphate dehydrogenase gene such as zwf can be overexpressed in the host organisms (Lim et al., J. Bioscience and Bioengineering, 2002, 93(6), 543-549).
In some embodiments, where pathways require excess NADPH co-factor in the synthesis of a C7 building block, a recombinant fructose 1,6 diphosphatase gene such as fbp can be overexpressed in the host organisms (Becker et al., J. Biotechnol., 2007, 132:99-109).
In some embodiments, where pathways require excess NADPH co-factor in the synthesis of a C7 building block, endogenous triose phosphate isomerase (EC 5.3.1.1) can be attenuated.
In some embodiments, where pathways require excess NADPH co-factor in the synthesis of a C7 building block, a recombinant glucose dehydrogenase such as the gene product of gdh can be overexpressed in the host organism (Satoh et al., J. Bioscience and Bioengineering, 2003, 95(4):335-341).
In some embodiments, endogenous enzymes facilitating the conversion of NADPH to NADH can be attenuated, such as the NADH generation cycle that may be generated via inter-conversion of glutamate dehydrogenases classified under EC 1.4.1.2 (NADH-specific) and EC 1.4.1.4 (NADPH-specific). For example, avoiding dissipation of an NADPH imbalance towards C7 building blocks, a NADH-specific glutamate dehydrogenase can be attenuated.
In some embodiments, an endogenous glutamate dehydrogenase (EC 1.4.1.3) that utilizes both NADH and NADPH as co-factors can be attenuated.
In some embodiments, a methanol dehydrogenase or a formaldehyde dehydrogenase can be overexpressed in the host to allow methanol catabolism via formate.
In some embodiments, a S-adenosylmethionine synthetase can be overexpressed in the host to generate S-Adenosyl-L-methionine as a co-factor for a fatty acid O-methyltransferase.
In some embodiments, one or more of 3-phosphoglycerate dehydrogenase, 3-phosphoserine aminotransferase and phosphoserine phosphatase can be overexpressed in the host to generate serine as a methyl donor for the S-Adenosyl-L-methionine cycle.
In some embodiments, a membrane-bound enoyl-CoA reductases can be solubilized via expression as a fusion protein to a small soluble protein such as a maltose binding protein (Gloerich et al., FEBS Letters, 2006, 580, 2092-2096).
In some embodiments, the efflux of a C7 building block across the cell membrane to the extracellular media can be enhanced or amplified by genetically engineering structural modifications to the cell membrane or increasing any associated transporter activity for a C7 building block.
The efflux of heptamethylenediamine can be enhanced or amplified by overexpressing broad substrate range multidrug transporters such as Blt from Bacillus subtilis (Woolridge et al., 1997, J. Biol. Chem., 272(14):8864-8866); AcrB and AcrD from Escherichia coli (Elkins & Nikaido, 2002, J. Bacteriol., 184(23), 6490-6499) or NorA from Staphylococcus aereus (Ng et al., 1994, Antimicrob Agents Chemother, 38(6), 1345-1355) or Bmr from Bacillus subtilis (Neyfakh, 1992, Antimicrob Agents Chemother, 36(2), 484-485).
The efflux of 7-aminoheptanoate and heptamethylenediamine can be enhanced or amplified by overexpressing the solute transporters such as the lysE transporter from Corynebacterium glutamicum (Bellmann et al., 2001, Microbiology, 147, 1765-1774).
The efflux of pimelic acid can be enhanced or amplified by overexpressing a dicarboxylate transporter such as the SucE transporter from Corynebacterium glutamicum (Huhn et al., Appl. Microbiol. & Biotech., 89(2), 327-335).
Producing C7 Building Blocks Using a Recombinant Host
Typically, one or more C7 building blocks can be produced by providing a host microorganism and culturing the provided microorganism with a culture medium containing a suitable carbon source as described above. In general, the culture media and/or culture conditions can be such that the microorganisms grow to an adequate density and produce a C7 building block efficiently. For large-scale production processes, any method can be used such as those described elsewhere (Manual of Industrial Microbiology and Biotechnology, 2nd Edition, Editors: A. L. Demain and J. E. Davies, ASM Press; and Principles of Fermentation Technology, P. F. Stanbury and A. Whitaker, Pergamon). Briefly, a large tank (e.g., a 100 gallon, 200 gallon, 500 gallon, or more tank) containing an appropriate culture medium is inoculated with a particular microorganism. After inoculation, the microorganism is incubated to allow biomass to be produced. Once a desired biomass is reached, the broth containing the microorganisms can be transferred to a second tank. This second tank can be any size. For example, the second tank can be larger, smaller, or the same size as the first tank. Typically, the second tank is larger than the first such that additional culture medium can be added to the broth from the first tank. In addition, the culture medium within this second tank can be the same as, or different from, that used in the first tank.
Once transferred, the microorganisms can be incubated to allow for the production of a C7 building block. Once produced, any method can be used to isolate C7 building blocks. For example, C7 building blocks can be recovered selectively from the fermentation broth via adsorption processes. In the case of pimelic acid and 7-aminoheptanoic acid, the resulting eluate can be further concentrated via evaporation, crystallized via evaporative and/or cooling crystallization, and the crystals recovered via centrifugation. In the case of heptamethylenediamine and 1,7-heptanediol, distillation may be employed to achieve the desired product purity.
Accordingly, the methods provided herein can be performed in a recombinant host. In some embodiments, the methods provided herein can be performed in a recombinant host by fermentation. In some embodiments, the recombinant host is subjected to a cultivation strategy under aerobic, anaerobic or, micro-aerobic cultivation conditions. In some embodiments, the recombinant host is cultured under conditions of nutrient limitation such as phosphate, nitrogen and oxygen limitation. In some embodiments, the recombinant host is retained using a ceramic membrane to maintain a high cell density during fermentation.
In some embodiments, the principal carbon source fed to the fermentation derives from biological or non-biological feedstocks. In some embodiments, the biological feedstock is, or derives from, monosaccharides, disaccharides, lignocellulose, hemicellulose, cellulose, lignin, levulinic acid, formic acid, triglycerides, glycerol, fatty acids, agricultural waste, condensed distillers' solubles, or municipal waste. In some embodiments, the non-biological feedstock is, or derives from, natural gas, syngas, CO2/H2, methanol, ethanol, benzoate, non-volatile residue (NVR) caustic wash waste stream from cyclohexane oxidation processes, or terephthalic acid/isophthalic acid mixture waste streams.
In some embodiments, the recombinant host is a prokaryote. In some embodiments, the prokaryote is from the genus Escherichia such as Escherichia coli; from the genus Clostridia such as Clostridium ljungdahlii, Clostridium autoethanogenum or Clostridium kluyveri; from the genus Corynebacteria such as Corynebacterium glutamicum; from the genus Cupriavidus such as Cupriavidus necalor or Cupriavidus metallidurans; from the genus Pseudomonas such as Pseudomonas fluorescens, Pseudomonas putida or Pseudomonas oleavorans; from the genus Delftia acidovorans, from the genus Bacillus such as Bacillus subtillis; from the genes Lactobacillus such as Lactobacillus delbrueckii; from the genus Lactococcus such as Lactococcus lactis; or from the genus Rhodococcus such as Rhodococcus equi. 
In some embodiments, the recombinant host is a eukaryote. In some embodiments, the eukaryote is from the genus Aspergillus such as Aspergillus niger; from the genus Saccharomyces such as Saccharomyces cerevisiae; from the genus Pichia such as Pichia pastoris; from the genus Yarrowia such as Yarrowia lipolytica, from the genus Issatchenkia such as Issathenkia orientalis, from the genus Debaryomyces such as Debaryomyces hansenii, from the genus Arxula such as Arxula adenoinivorans, or from the genus Kluyveromyces such as Kluyveromyces lactis. 
In some embodiments, the recombinant host includes one or more of the following polypeptides having attenuated activity: polyhydroxyalkanoate synthase activity, acetyl-CoA thioesterase activity, acetyl-CoA specific β-ketothiolase activity, phosphotransacetylase forming acetate activity, acetate kinase activity, lactate dehydrogenase activity, menaquinol-fumarate oxidoreductase activity, 2-oxoacid decarboxylase producing isobutanol, alcohol dehydrogenase activity forming ethanol, triose phosphate isomerase activity, pyruvate decarboxylase activity, glucose-6-phosphate isomerase activity, transhydrogenase activity dissipating the NADPH imbalance, glutamate dehydrogenase activity dissipating the NADPH imbalance, NADH/NADPH-utilizing glutamate dehydrogenase activity, pimeloyl-CoA dehydrogenase activity; acyl-CoA dehydrogenase activity accepting C7 building blocks and central precursors as substrates; glutaryl-CoA dehydrogenase activity; or pimeloyl-CoA synthetase activity.
In some embodiments, the recombinant host overexpresses one or more genes encoding a polypeptide having: acetyl-CoA synthetase activity; transketolase activity; puridine nucleotide transhydrogenase activity; formate dehydrogenase activity; glyceraldehyde-3P-dehydrogenase activity; malic enzyme activity; glucose-6-phosphate dehydrogenase activity; fructose 1,6 diphosphatase activity; L-alanine dehydrogenase activity; PEP carboxylase activity, pyruvate carboxylase activity; PEP carboxykinase activity; PEP synthase activity; L-glutamate dehydrogenase activity specific to the NADPH used to generate a co-factor imbalance; methanol dehydrogenase activity, formaldehyde dehydrogenase activity, lysine transporter activity; dicarboxylate transporter activity; S-adenosylmethionine synthetase activity; 3-phosphoglycerate dehydrogenase activity; 3-phosphoserine aminotransferase activity; phosphoserine phosphatase activity; or a multidrug transporter activity.
The present document further provides a recombinant host comprising at least one exogenous nucleic acid encoding having (i) β-ketoacyl-[acp] synthase activity or β-ketothiolase activity, (ii) 3-hydroxybutyryl-CoA dehydrogenase activity, and (iii) enoyl-CoA hydratase activity.
In some embodiments, the recombinant host further includes one or more exogenous polypeptides having homocitrate synthase, homocitrate dehydratase, homoaconitate hydratase, isohomocitrate dehydrogenase, 2-hydroxyglutarate dehydrogenase, glutaconate CoA-tramsferase, or 2-hydroxyglutaryl-CoA dehydratase activity.
In some embodiments, the recombinant host further includes one or more exogenous polypeptides having glutarate semialdehyde dehydrogenase, 4-hydroxy-2-oxoheptanedioate aldolase, 2-oxo-hept-3-ene-1,7-dioate hydratase, 2-en oate reductase, 2-hydroxyglutarate dehydrogenase, glutaconate CoA-transferase, or 2-hydroxyglutaryl-CoA dehydratase activity.
In some embodiments, the recombinant host further includes one or more exogenous polypeptides having thioesterase, aldehyde dehydrogenase, 7-oxoheptanoate dehydrogenase, 6-oxohexanoate dehydrogenase, glutaconate CoA-transferase, reversible succinyl-CoA ligase, acetylating aldehyde dehydrogenase, or carboxylate reductase activity, the host further producing pimelic acid or pimelate semialdehyde.
In some embodiments, the recombinant host further includes an exogenous polypeptide having ω-transaminase activity, the host further producing 7-aminoheptanoate.
In some embodiments, the recombinant host further includes one or more exogenous polypeptides having 4-hydroxybutyrate dehydrogenase, 5-hydroxypentanoate dehydrogenase, 6-hydroxyhexanoate dehydrogenase, or alcohol dehydrogenase activity, the host further producing 7-hydroxyheptanoic acid.
In some embodiments, the recombinant host further includes one or more exogenous polypeptides having ω-transaminase, deacetylase, N-acetyl transferase, or alcohol dehydrogenase activity, the host further producing heptamethylenediamine.
In some embodiments, the recombinant host further includes one or more exogenous polypeptides having (a) carboxylate reductase activity enhanced by phosphopantetheinyl transferase activity, or (b) alcohol dehydrogenase activity, the host further producing 1,7-heptanediol.
The invention is further described in the following examples, which do not limit the scope of the invention described in the claims.
EXAMPLES
Example 1
Enzyme Activity of Thioesterases Using Pimeloyl-CoA as a Substrate and Forming Pimelic Acid
A sequence encoding an N-terminal His tag was added to the tesB gene from Escherichia coli that encodes a thioesterase (SEQ ID NO: 21, see FIG. 9K), such that an N-terminal HIS tagged thioesterase could be produced. The modified tesB gene was cloned into a pET15b expression vector under control of the T7 promoter. The expression vector was transformed into a BL21[DE3] E. coli host. The resulting recombinant E. coli strain was cultivated at 37° C. in a 500 mL shake flask culture containing 50 mL Luria Broth (LB) media and antibiotic selection pressure, with shaking at 230 rpm. The culture was induced overnight at 17° C. using 0.5 mM IPTG.
The pellet from the induced shake flask culture was harvested via centrifugation. The pellet was resuspended and lysed in Y-perTM solution (ThermoScientific, Rockford, Ill.). The cell debris was separated from the supernatant via centrifugation. The thioesterase was purified from the supernatant using Ni-affinity chromatography and the eluate was buffer exchanged and concentrated via ultrafiltration.
The enzyme activity assay was performed in triplicate in a buffer composed of 50 mM phosphate buffer (pH=7.4), 0.1 mM Ellman's reagent, and 667 μM of pimeloyl-CoA (as substrate). The enzyme activity assay reaction was initiated by adding 0.8 μM of the tesB gene product to the assay buffer containing the pimeloyl-CoA and incubating at 37° C. for 20 minutes. The release of Coenzyme A was monitored by absorbance at 412 nm. The absorbance associated with the substrate only control, which contained boiled enzyme, was subtracted from the active enzyme assay absorbance and compared to the empty vector control. The gene product of tesB accepted pimeloyl-CoA as substrate as confirmed via relative spectrophotometry (see, FIG. 10) and synthesized pimelate as a reaction product.
Example 2
Enzyme Activity of ω-Transaminase Using Pimelate Semialdehyde as Substrate and Forming 7-Aminoheptanoate
A sequence encoding an N-terminal His-tag was added to the genes from Chromobacterium violaceum, Pseudomonas syringae, Rhodobacter sphaeroides, and Vibrio fluvialis encoding the ω-transaminases of SEQ ID NOs: 13, 15, 16, and 18, respectively (see, FIGS. 9I and 9J) such that N-terminal HIS tagged ω-transaminases could be produced. Each of the resulting modified genes was cloned into a pET21a expression vector under control of the T7 promoter and each expression vector was transformed into a BL21 [DE3] E. coli host. The resulting recombinant E. coli strains were cultivated at 37° C. in a 250 mL shake flask culture containing 50 mL LB media and antibiotic selection pressure, with shaking at 230 rpm. Each culture was induced overnight at 16° C. using 1 mM IPTG.
The pellet from each induced shake flask culture was harvested via centrifugation. Each pellet was resuspended and lysed via sonication. The cell debris was separated from the supernatant via centrifugation and the cell free extract was used immediately in enzyme activity assays.
Enzyme activity assays in the reverse direction (i.e., 7-aminoheptanoate to pimelate semialdehyde) were performed in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 10 mM 7-aminoheptanoate, 10 mM pyruvate and 100 μM pyridoxyl 5′ phosphate. Each enzyme activity assay reaction was initiated by adding cell free extract of the ω-transaminase gene product or the empty vector control to the assay buffer containing the 7-aminoheptanoate and incubated at 25° C. for 4 hours, with shaking at 250 rpm. The formation of L-alanine from pyruvate was quantified via RP-HPLC.
Each enzyme only control without 7-aminoheptanoate demonstrated low base line conversion of pyruvate to L-alanine. See, FIG. 16. The gene product of SEQ ID NO: 13, SEQ ID NO: 15, SEQ ID NO: 16, and SEQ ID NO: 18 accepted 7-aminoheptanote as substrate as confirmed against the empty vector control. See, FIG. 17.
Enzyme activity in the forward direction (i.e., pimelate semialdehyde to 7-aminoheptanoate) was confirmed for the transaminases of SEQ ID NO: 15, SEQ ID NO: 16, and SEQ ID NO: 18. Enzyme activity assays were performed in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 10 mM pimelate semialdehyde, 10 mM L-alanine and 100 μM pyridoxyl 5′ phosphate. Each enzyme activity assay reaction was initiated by adding a cell free extract of the ω-transaminase gene product or the empty vector control to the assay buffer containing the pimelate semialdehyde and incubated at 25° C. for 4 hours, with shaking at 250 rpm. The formation of pyruvate was quantified via RP-HPLC.
The gene product of SEQ ID NO: 15, SEQ ID NO: 16, and SEQ ID NO: 18 accepted pimelate semialdehyde as substrate as confirmed against the empty vector control. See, FIG. 18. The reversibility of the ω-transaminase activity was confirmed, demonstrating that the ω-transaminases of SEQ ID NO: 13, SEQ ID NO: 15, SEQ ID NO: 16, and SEQ ID NO: 18 accepted pimelate semialdehyde as substrate and synthesized 7-aminoheptanoate as a reaction product.
Example 3
Enzyme Activity of Carboxylate Reductase Using Pimelate as Substrate and Forming Pimelate Semialdehyde
A sequence encoding a HIS-tag was added to the genes from Segniliparus rugosus and Segniliparus rotundus that encode the carboxylate reductases of SEQ ID NOs: 9 and 12, respectively (see FIGS. 9E and 9H), such that N-terminal HIS tagged carboxylate reductases could be produced. Each of the modified genes was cloned into a pET Duet expression vector along with a sfp gene encoding a HIS-tagged phosphopantetheine transferase from Bacillus subtilis, both under the T7 promoter. Each expression vector was transformed into a BL21 [DE3] E. coli host and the resulting recombinant E. coli strains were cultivated at 37° C. in a 250 mL shake flask culture containing 50 mL LB media and antibiotic selection pressure, with shaking at 230 rpm. Each culture was induced overnight at 37° C. using an auto-induction media.
The pellet from each induced shake flask culture was harvested via centrifugation. Each pellet was resuspended and lysed via sonication, and the cell debris was separated from the supernatant via centrifugation. The carboxylate reductases and phosphopantetheine transferases were purified from the supernatant using Ni-affinity chromatography, diluted 10-fold into 50 mM HEPES buffer (pH=7.5), and concentrated via ultrafiltration.
Enzyme activity assays (i.e., from pimelate to pimelate semialdehyde) were performed in triplicate in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 2 mM pimelate, 10 mM MgCl2, 1 mM ATP and 1 mM NADPH. Each enzyme activity assay reaction was initiated by adding purified carboxylate reductase and phosphopantetheine transferase gene products or the empty vector control to the assay buffer containing the pimelate and then incubated at room temperature for 20 minutes. The consumption of NADPH was monitored by absorbance at 340 nm. Each enzyme only control without pimelate demonstrated low base line consumption of NADPH. See, FIG. 11.
The gene products of SEQ ID NO: 9 and SEQ ID NO: 12, enhanced by the gene product of sfp, accepted pimelate as substrate, as confirmed against the empty vector control (see FIG. 12), and synthesized pimelate semialdehyde.
Example 4
Enzyme Activity of Carboxylate Reductase Using 7-Hydroxyheptanoate as Substrate and Forming 7-Hydroxyheptanal
A sequence encoding a His-tag was added to the genes from Mycobacterium marinum, Mycobacterium smegmatis, Segniliparus rugosus, Mycobacterium smegmatis, Mycobacterium massiliense, and Segniliparus rotundus that encode the carboxylate reductases of SEQ ID NOs: 7 to 12 respectively (see, FIGS. 9C-9H) such that N-terminal HIS tagged carboxylate reductases could be produced. Each of the modified genes was cloned into a pET Duet expression vector alongside a sfp gene encoding a His-tagged phosphopantetheine transferase from Bacillus subtilis, both under control of the T7 promoter.
Each expression vector was transformed into a BL21 [DE3] E. coli host and the resulting recombinant E. coli strains were cultivated at 37° C. in a 250 mL shake flask culture containing 50 mL LB media and antibiotic selection pressure, with shaking at 230 rpm. Each culture was induced overnight at 37° C. using an auto-induction media.
The pellet from each induced shake flask culture was harvested via centrifugation. Each pellet was resuspended and lysed via sonication. The cell debris was separated from the supernatant via centrifugation. The carboxylate reductases and phosphopantetheine transferase were purified from the supernatant using Ni-affinity chromatography, diluted 10-fold into 50 mM HEPES buffer (pH=7.5) and concentrated via ultrafiltration.
Enzyme activity (i.e., 7-hydroxyheptanoate to 7-hydroxyheptanal) assays were performed in triplicate in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 2 mM 7-hydroxyheptanoate, 10 mM MgCl2, 1 mM ATP, and 1 mM NADPH. Each enzyme activity assay reaction was initiated by adding purified carboxylate reductase and phosphopantetheine transferase or the empty vector control to the assay buffer containing the 7-hydroxyheptanoate and then incubated at room temperature for 20 min. The consumption of NADPH was monitored by absorbance at 340 nm. Each enzyme only control without 7-hydroxyheptanoate demonstrated low base line consumption of NADPH. See, FIG. 11.
The gene products of SEQ ID NOs: 7 to 12, enhanced by the gene product of sfp, accepted 7-hydroxyheptanoate as substrate as confirmed against the empty vector control (see, FIG. 13), and synthesized 7-hydroxyheptanal.
Example 5
Enzyme Activity of ω-Transaminase for 7-Aminoheptanol, Forming 7-Oxoheptanol
A nucleotide sequence encoding an N-terminal His-tag was added to the Chromobacterium violaceum, Pseudomonas syringae and Rhodobacter sphaeroides genes encoding the ω-transamtinases of SEQ ID NOs: 13, 15, and 16, respectively (see, FIGS. 9I and 9J) such that N-terminal HIS tagged ω-transaminases could be produced. The modified genes were cloned into a pET21a expression vector under the T7 promoter. Each expression vector was transformed into a BL21 [DE3] E. coli host. Each resulting recombinant E. coli strain were cultivated at 37° C. in a 250 mL shake flask culture containing 50 mL LB media and antibiotic selection pressure, with shaking at 230 rpm. Each culture was induced overnight at 16° C. using 1 mM IPTG.
The pellet from each induced shake flask culture was harvested via centrifugation. Each pellet was resuspended and lysed via sonication. The cell debris was separated from the supernatant via centrifugation and the cell free extract was used immediately in enzyme activity assays.
Enzyme activity assays in the reverse direction (i.e., 7-aminoheptanol to 7-oxoheptanol) were performed in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 10 mM 7-aminoheptanol, 10 mM pyruvate, and 100 μM pyridoxyl 5′ phosphate. Each enzyme activity assay reaction was initiated by adding cell free extract of the ω-transaminase gene product or the empty vector control to the assay buffer containing the 7-aminoheptanol and then incubated at 25° C. for 4 hours, with shaking at 250 rpm. The formation of L-alanine was quantified via RP-HPLC.
Each enzyme only control without 7-aminoheptanol had low base line conversion of pyruvate to L-alanine. See, FIG. 16.
The gene products of SEQ ID NOs: 13, 15, and 16 accepted 7-aminoheptanol as substrate as confirmed against the empty vector control (see FIG. 21) and synthesized 7-oxoheptanol as reaction product. Given the reversibility of the ω-transaminase activity (see Example 2), it can be concluded that the gene products of SEQ ID NOs.: 13, 15, and 16 accept 7-oxoheptanol as substrate and form 7-aminoheptanol.
Example 6
Enzyme Activity of ω-Transaminase Using Heptamethylenediamine as Substrate and Forming 7-Aminoheptanal
A sequence encoding an N-terminal His-tag was added to the Chromobacterium violaceum, Pseudomonas aeruginosa, Pseudomonas syringae, Rhodobacter sphaeroides, Escherichia coli, and Vibrio fluvialis genes encoding the ω-transaminases of SEQ ID NOs: 13 to 18, respectively (see, FIGS. 9I and 9J) such that N-terminal HIS tagged ω-transaminases could be produced. The modified genes were cloned into a pET21a expression vector under the T7 promoter. Each expression vector was transformed into a BL21[DE3] E. coli host. Each resulting recombinant E. coli strain were cultivated at 37° C. in a 250 mL shake flask culture containing 50 mL LB media and antibiotic selection pressure, with shaking at 230 rpm. Each culture was induced overnight at 16° C. using 1 mM IPTG.
The pellet from each induced shake flask culture was harvested via centrifugation. Each pellet was resuspended and lysed via sonication. The cell debris was separated from the supernatant via centrifugation and the cell free extract was used immediately in enzyme activity assays.
Enzyme activity assays in the reverse direction (i.e., heptamethylenediamine to 7-aminoheptanal) were performed in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 10 mM heptamethylenediamine, 10 mM pyruvate, and 100 μM pyridoxyl 5′ phosphate. Each enzyme activity assay reaction was initiated by adding cell free extract of the ω-transaminase gene product or the empty vector control to the assay buffer containing the heptamethylenediamine and then incubated at 25° C. for 4 hours, with shaking at 250 rpm. The formation of L-alanine was quantified via RP-HPLC.
Each enzyme only control without heptamethylenediamine had low base line conversion of pyruvate to L-alanine. See, FIG. 16.
The gene products of SEQ ID NOs: 13 to 18 accepted heptamethylenediamine as substrate as confirmed against the empty vector control (see, FIG. 19) and synthesized 7-aminoheptanal as reaction product. Given the reversibility of the ω-transaminase activity (see Example 2), it can be concluded that the gene products of SEQ ID NOs: 13 to 18 accept 7-aminoheptanal as substrate and form heptamethylenediamine.
Example 7
Enzyme Activity of Carboxylate Reductase for N7-Acetyl-7-Aminoheptanoate, Forming N7-Acetyl-7-Aminoheptanal
The activity of each of the N-terminal His-tagged carboxylate reductases of SEQ ID NOs: 8, 11, and 12 (see Example 4, and FIGS. 9D, 9G, and 9H) for converting N7-acetyl-7-aminoheptanoate to N7-acetyl-7-aminoheptanal was assayed in triplicate in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 2 mM N7-acetyl-7-aminoheptanoate, 10 mM MgCl2, 1 mM ATP, and 1 mM NADPH. The assays were initiated by adding purified carboxylate reductase and phosphopantetheine transferase or the empty vector control to the assay buffer containing the N7-acetyl-7-aminoheptanoate then incubated at room temperature for 20 minutes. The consumption of NADPH was monitored by absorbance at 340 nm. Each enzyme only control without N7-acetyl-7-aminoheptanoate demonstrated low base line consumption of NADPH. See, FIG. 11.
The gene products of SEQ ID NOs: 8, 11, and 12 enhanced by the gene product of sfp, accepted N7-acetyl-7-aminoheptanoate as substrate as confirmed against the empty vector control (see, FIG. 14), and synthesized N7-acetyl-7-aminoheptanal.
Example 8
Enzyme Activity of ω-Transaminase Using N7-Acetyl-1,7-Diaminoheptane, and Forming N7-Acetyl-7-Aminoheptanal
The activity of the N-terminal His-tagged ω-transaminases of SEQ ID NOs: 13 to 18 (see, Example 6, and FIGS. 9I and 9J) for converting N7-acetyl-1,7-diaminoheptane to N7-acetyl-7-aminoheptanal was assayed using a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 10 mM N7-acetyl-1,7-diaminoheptane, 10 mM pyruvate and 100 μM pyridoxyl 5′ phosphate. Each enzyme activity assay reaction was initiated by adding a cell free extract of the ω-transaminase or the empty vector control to the assay buffer containing the N7-acetyl-1,7-diaminoheptane then incubated at 25° C. for 4 hours, with shaking at 250 rpm. The formation of L-alanine was quantified via RP-HPLC.
Each enzyme only control without N7-acetyl-1,7-diaminoheptane demonstrated low base line conversion of pyruvate to L-alanine. See, FIG. 16.
The gene product of SEQ ID NOs: 13 to 18 accepted N7-acetyl-1,7-diaminoheptane as substrate as confirmed against the empty vector control (see FIG. 20) and synthesized N7-acetyl-7-aminoheptanal as reaction product.
Given the reversibility of the ω-transaminase activity (see example 2), the gene products of SEQ ID NOs: 13 to 18 accept N7-acetyl-7-aminoheptanal as substrate forming N7-acetyl-1,7-diaminoheptane.
Example 9
Enzyme Activity of Carboxylate Reductase Using Pimelate Semialdehyde as Substrate and Forming Heptanedial
The N-terminal His-tagged carboxylate reductase of SEQ ID NO: 12 (see, Example 4 and FIG. 9H) was assayed using pimelate semialdehyde as substrate. The enzyme activity assay was performed in triplicate in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 2 mM pimelate semialdehyde, 10 mM MgCl2, 1 mM ATP and 1 mM NADPH. The enzyme activity assay reaction was initiated by adding purified carboxylate reductase and phosphopantetheine transferase or the empty vector control to the assay buffer containing the pimelate semialdehyde and then incubated at room temperature for 20 minutes. The consumption of NADPH was monitored by absorbance at 340 nm. The enzyme only control without pimelate semialdehyde demonstrated low base line consumption of NADPH. See, FIG. 11.
The gene product of SEQ ID NO: 12, enhanced by the gene product of sfp, accepted pimelate semialdehyde as substrate as confirmed against the empty vector control (see, FIG. 15) and synthesized heptanedial.
Example 10
Enzyme Activity of Pimeloyl-[Acp] Methyester Methylesterase Using Pimeloyl-CoA Methyl Ester as Substrate and Forming Pimeloyl-CoA
A nucleotide sequence encoding a C-terminal His-tag was added to the gene from Escherichia coli encoding the pimeloyl-[acp] methylester methylesterase of SEQ ID NO: 6 (see, FIG. 9B) such that a C-terminal HIS tagged pimeloyl-[acp] methyl ester methylesterase could be produced. The resulting modified gene was cloned into a pET28b+ expression vector under control of the T7 promoter and the expression vector was transformed into a BL21 [DE3] E. coli host. The resulting recombinant E. coli strain was cultivated at 37° C. in a 500 mL shake flask culture containing 100 mL LB media and antibiotic selection pressure, with shaking at 230 rpm. Each culture was induced overnight at 18° C. using 0.3 mM IPTG.
The pellet from each induced shake flask culture was harvested via centrifugation. Each pellet was resuspended and lysed via sonication. The cell debris was separated from the supernatant via centrifugation. The pimeloyl-[acp] methyl ester methylesterase was purified from the supernatant using Ni-affinity chromatography, buffer exchanged and concentrated into 20 mM HEPES buffer (pH=7.5) via ultrafiltration and stored at 4° C.
Enzyme activity assays converting pimeloyl-CoA methyl ester to pimeloyl-CoA were performed in triplicate in a buffer composed of a final concentration of 25 mM Tris.HCl buffer (pH=7.0) and 5 [mM] pimeloyl-CoA methyl ester. The enzyme activity assay reaction was initiated by adding pimeloyl-[acp] methyl ester methylesterase to a final concentration of 10 [μM] to the assay buffer containing the pimeloyl-CoA methyl ester and incubated at 30° C. for 1 hour, with shaking at 250 rpm. The formation of pimeloyl-CoA was quantified via LC-MS.
The substrate only control without enzyme demonstrated no conversion of the substrate pimeloyl-CoA methyl ester to pimeloyl-CoA. See, FIG. 22. The pimeloyl-[acp]methyl ester methylesterase of SEQ ID NO: 6 accepted pimeloyl-CoA methyl ester as substrate and synthesized pimeloyl-CoA as reaction product as confirmed via LC-MS. See, FIG. 22.
Example 11
Enzyme Activity of 6Ketothiolases Using Glutaryl-CoA and Acetyl-CoA as Substrates and Forming 3-Ketopimeloyl-CoA
A nucleotide sequence encoding a N-terminal His-tag was added to the gene from Pseudomonas reinekei MT1, Pseudomonas putida, Burkholderia xenovorans, Arthrobacter sp., Burkholderia xenovorans, Geobacillus kaustophilus, Gordonia bronchialis, Citrobacter freundii, Burkholderia sp., Beijerinckia indica, Arthrobacter arilaitensis, Cupriavidus necator and Escherichia coli encoding the β-ketothiolase of SEQ ID NOs: 28 to 40 (see, FIGS. 9M-9Q) such that a N-terminal HIS tagged β-ketothiolase could be produced. The resulting modified gene was cloned into a pET15b expression vector under control of the T7 promoter and the expression vector was transformed into a BL21[DE3] E. coli host. The resulting recombinant E. coli strain was cultivated at 37° C. in a 1 L shake flask culture containing 350 mL LB media and ampicilin antibiotic selection pressure, with shaking at 230 rpm. Each culture was induced overnight at 25° C. using 1 mM IPTG.
The pellet from each induced shake flask culture was harvested via centrifugation. Each pellet was resuspended and lysed via sonication. The cell debris was separated from the supernatant via centrifugation. The β-ketothiolase was purified from the supernatant using Ni-affinity chromatography, buffer exchanged and concentrated into 50 mM potassium phosphate buffer (pH=6.8) via ultrafiltration.
Enzyme activity assays converting glutaryl-CoA and acetyl-CoA to 3-ketopimeloyl-CoA were performed in triplicate in a buffer composed of a final concentration of 50 mM potassium phosphate buffer (pH=6.8) and 1 mM glutaryl-CoA and 1 mM acetyl-CoA. The enzyme activity assay reaction was initiated by adding β-ketothiolase to a final concentration of 7 [μM] to the assay buffer containing the 1 mM glutaryl-CoA and 1 mM acetyl-CoA and incubated at 30° C. for three hours, with gentle shaking. The formation of 3-ketopimeloyl-CoA was quantified via LC-MS.
The substrate only control without enzyme demonstrated no conversion of the substrate pimeloyl-CoA methyl ester to pimeloyl-CoA. See, FIG. 23. The β-ketothiolase of SEQ ID NOs: 28 to 40 accepted glutaryl-CoA and acetyl-CoA as substrates and synthesized 3-ketopimeloyl-CoA as reaction product as confirmed via LC-MS against the empty vector control. See, FIG. 23.
OTHER EMBODIMENTS
It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims.

## Claims

1. A method of shielding a carbon chain aliphatic backbone, functionalized with terminal carboxyl groups, in a recombinant host using at least one exogenous polypeptide expressed by said host, said method comprising:
enzymatically converting a n-carboxy-2-enoic acid to a n-carboxy-2-enoate methyl ester in said host by contacting said n-carboxy-2-enoic acid with a polypeptide having fatty acid O-methyltransferase activity, wherein n+1 reflects the length of the carbon chain aliphatic backbone and the polypeptide having fatty acid O-methyltransferase activity has at least 85% sequence identity to any one of the amino acid sequences set forth in SEQ ID NOs: 1-3.

2. A method of producing 2(E)-heptenedioyl-CoA methyl ester in a recombinant host using at least one exogenous polypeptide expressed by said host, said method comprising:
enzymatically converting 2(E)-heptenedioate to 2(E)-heptenedioate methyl ester by contacting 2(E)-heptenedioate with a polypeptide having fatty acid O-methyltransferase activity, wherein said polypeptide having fatty acid O-methyltransferase activity has at least 85% sequence identity to any one of the amino acid sequences set forth in SEQ ID NOs: 1-3;
enzymatically converting 2(E)-heptenedioate methyl ester to 2(E)-heptenedioyl-CoA methyl ester by contacting 2(E)-heptenedioate methyl ester with a polypeptide having the activity of a CoA ligase, wherein said polvpeptide having the activity of a CoA ligase has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 22 or SEQ ID NO: 23;
enzymatically converting 2(E)-heptenedioyl-CoA methyl ester to pimeloyl-CoA methyl ester by contacting 2(E)-heptenedioyl-CoA methyl ester with a polypeptide having the activity of a trans-2-enoyl-CoA reductase, wherein said polvpeptide having the activity of a trans-2-enoyl-CoA reductase has at least 85% sequence identity to the amino acid sequence of SEQ ID NO: 26 or SEQ ID NO: 27; and
enzymatically converting pimeloyl-CoA methyl ester to pimeloyl-CoA by contacting pimeloyl-CoA methyl ester with a polypeptide having the activity of a pimelyl-[acp]methyl ester esterase, wherein said polypeptide having the activity of a pimelyl-[acp]methyl ester esterase has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 6.

3. The method of claim 2, further comprising enzymatically converting pimeloyl-CoA to a product selected from pimelic acid, pimelate semialdehyde, 7-aminoheptanoate, 7-hydroxyheptanoate, heptamethylenediamine, and 1.7-heptanediol, wherein pimeloyl-CoA is converted to said product using at least one exogenous polypeptide expressed by said host, wherein said exogenous polypeptide has thioesterase, reversible CoA-ligase, glutaconate CoA-transferase, ω-transaminase, 6-hydroxyhexanoate dehydrogenase, 5-hydroxypentanoate dehydrogenase, 4-hydroxybutyrate dehydrogenase, alcohol dehydrogenase, carboxylate reductase, or phosphopantetheine transferase enhancer activity, wherein:
said polypeptide having the activity of a thioesterase has at least 85% sequence similarity to the amino acid sequence set forth in any one of SEQ ID NOs: 4, 5, or 21;
said polypeptide having the activity of a reversible CoA-ligase is classified under EC 6.2.1.5;
said polypeptide having the activity of a glutaconate CoA-transferase has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 24 and SEQ ID NO: 25;
said polypeptide having the activity of a ω-transaminase has at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 13-18;
said polypeptide having the activity of a 6-hydroxyhexanoate dehydrogenase has at least 85% sequence identity to the amino acid sequence of a gene product of chnD;
said polypeptide having the activity of a 5-hydroxypentanoate dehydrogenase has at least 85% sequence identity to the amino acid sequence of a gene product of cpnD;
said polypeptide having the activity of a 4-hydroxybutyrate dehydrogenase has at least 85% sequence identity to the amino acid sequence of a gene product of gbd;
said polypeptide having the activity of an alcohol dehydrogenase has at least 85% sequence identity to the amino acid seauence of a gene product of any one of hadH, IdhA, yghD, or YMR318C or the amino acid sequence of the protein having GenBank Accession No. CAA81612.1;
said polypeptide having the activity of a carboxylate reductase has at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 7-12; and
said polypeptide having the activity of a phosphopantetheine transferase enhancer has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 19 or SEQ ID NO: 20 or at least 85% sequence identity to the amino acid sequence of the gene products of griC and griD.

4. The method of claim 3, wherein said product is pimelate semialdehyde and said method comprises:
contacting pimeloyl-CoA with a polypeptide having acetylating aldehyde dehydrogenase activity, wherein said polypeptide having acetylating aldehyde dehydrogenase activity has at least 85% seauence identity to the amino acid sequence of the gene product of pduB or pduP; or
contacting pimeloyl-CoA with a polypeptide having thioesterase, reversible CoA-ligase, or glutaconate CoA-transferase activity to produce pimelic acid and contacting pimelic acid with a polypeptide having carboxylate reductase activity optionally in combination with a polypeptide having the activity of a phosphopantetheine transferase enhancer to produce pimelate semialdehyde, wherein
said polypeptide having thioesterase activity has at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 4, 5, or 21;
said polypeptide having reversible CoA-ligase activity is classified under EC 6.2.1.5;
said polypeptide having glutaconate CoA-transferase activity has at least 85% sequence identity to SEQ ID NOs: 24 and 25;
said polypeptide having the activity of a carboxylate reductase has at least 85% seauence identity to the amino acid seauence set forth in any one of SEQ ID NOs: 7-12; and
said polypeptide having the activity of a phosphopantetheine transferase enhancer has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 19 or SEQ ID NO: 20 or at least 85% sequence identity to the amino acid sequence of the gene products of griC and griD.

5. The method of claim 4, said method further comprising
enzymatically converting pimelate semialdehyde to 7-aminoheptanoate by contacting pimelate semialdehyde with a polypeptide having ω-transaminase activity, wherein said polypeptide having ω-transaminase activity has at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 13-18.

6. The method of claim 1, wherein one or more steps of said method are performed by fermentation.

7. The method of claim 1, wherein said recombinant host is subjected to a cultivation strategy under aerobic, anaerobic, micro-aerobic, or mixed oxygen/denitrification cultivation conditions.

8. The method of claim 1, wherein said recombinant host is cultured under conditions of phosphate, oxygen, and/or nitrogen limitation.

9. The method of claim 1, wherein said recombinant host is retained using a ceramic membrane to maintain a high cell density during fermentation.

10. The method of claim 6, wherein the principal carbon source fed to the fermentation derives from biological or non-biological feedstocks, wherein
the biological feedstock is, or derives from, monosaccharides, disaccharides, lignocellulose, hemicellulose, cellulose, lignin, levulinic acid, formic acid, triglycerides, glycerol, fatty acids, agricultural waste, condensed distillers' solubles, or municipal waste; and
wherein the non-biological feedstock is, or derives from, natural gas, syngas, CO2/H2, methanol, ethanol, benzoate, non-volatile residue (NVR) caustic wash waste stream from cyclohexane oxidation processes, or terephthalic acid/isophthalic acid mixture waste streams.

11. The method of claim 6, wherein said recombinant host comprises one or more polypeptides having attenuated polyhydroxyalkanoate synthase, acetyl-CoA thioesterase, acetyl-CoA specific β-ketothiolase, phosphotransacetylase forming acetate, acetate kinase, lactate dehydrogenase, menaquinol-fumarate oxidoreductase, 2-oxoacid decarboxylase producing isobutanol, alcohol dehydrogenase forming ethanol, triose phosphate isomerase, pyruvate decarboxylase, glucose-6-phosphate isomerase, transhydrogenase dissipating the NADPH imbalance, glutamate dehydrogenase dissipating the NADPH imbalance, NADH/NADPH-utilizing glutamate dehydrogenase, pimeloyl-CoA dehydrogenase, acyl-CoA dehydrogenase accepting C7 building blocks and central precursors as substrates, glutaryl-CoA dehydrogenase, or pimeloyl-CoA synthetase activity, and optionally wherein the recombinant host overexpresses one or more genes encoding a polypeptide having acetyl-CoA synthetase, 6-phosphogluconate dehydrogenase, transketolase, puridine nucleotide transhydrogenase, formate dehydrogenase, glyceraldehyde-3P-dehydrogenase, malic enzyme, glucose-6-phosphate dehydrogenase, fructose 1,6 diphosphatase, L-alanine dehydrogenase, PEP carboxylase, pyruvate carboxylase, PEP carboxykinase, PEP synthase, L-glutamate dehydrogenase specific to the NADPH used to generate a co-factor imbalance, methanol dehydrogenase, formaldehyde dehydrogenase, lysine transporter, dicarboxylate transporter, S-adenosylmethionine synthetase, 3-phosphoglycerate dehydrogenase, 3 phosphoserine aminotransferase, phosphoserine phosphatase, or a multidrug transporter activity.

12. The method of claim 1, wherein the host is:
a prokaryote selected from the genus Escherichia, Clostridia, Corynebacteria, Cupriavidus, Pseudomonas, Delftia, Bacilluss, Lactobacillus, Lactococcus, or Rhodococcus; or
a eukaryote selected from the genus Aspergillus, Saccharomyces, Pichia, Yarrowia, Issatchenkia, Debaryomyces, Arxula, or Kluyveromyces.

13. The method of claim 1, wherein the n-carboxy-2-enoic acid is 2(E) heptenedioic acid and the n-carboxy-2-enoate methyl ester is 2(E)-heptenedioate methyl ester.

14. The method of claim 2, wherein 2(E)-heptenedioate is enzymatically produced from 2(E)-heptenedioyl-CoA by contacting 2(E)-heptenedioyl-CoA with a polypeptide having thioesterase or glutaconate CoA-transferase activity, wherein said polypeptide having thioesterase activity has at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 4, 5, or 21 and said polypeptide having CoA-transferase activity has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 24 or SEQ ID NO: 25.

15. The method of claim 3, wherein said product is pimelic acid and said method comprises contacting pimeloyl-CoA with a polypeptide having thioesterase, reversible CoA-ligase, or glutaconate CoA-transferase activity, wherein
said polypeptide having thioesterase activity has at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 4, 5, or 21;
said polypeptide having reversible CoA-ligase activity is classified under EC 6.2.1.5; and
said polypeptide having glutaconate CoA-transferase activity has at least 85% sequence identity to SEQ ID NOs: 24 and 25.

16. The method of claim 4, said method further comprising enzymatically converting pimelate semialdehyde to pimelic acid by contacting pimelate semialdehyde with a polypeptide having the activity of a 7-oxoheptanoate dehydrogenase, 6-oxohexanoate dehydrogenase, or 5-oxopentanoate dehydrogenase, wherein
said polypeptide having the activity of a 7-oxoheptanoate dehydrogenase has at least 85% sequence identity to the amino acid sequence of the gene product of thnG;
said polypeptide having the activity of a 6-oxohexanoate dehydrogenase has at least 85% sequence identity to the amino acid sequence of the gene product of chnE; and
said polypeptide having the activity of a 5-oxopentanoate dehydrogenase has at least 85% sequence identity to the amino acid sequence of the gene product of cpnE.

17. The method of claim 4, said method further comprising enzymatically converting pimelate semialdehyde to heptamethylenediamine by contacting pimelate semialdehyde with a polypeptide having the activity of a carboxylate reductase optionally in combination with a polypeptide having the activity of a phosphopantetheine transferase enhancer to produce heptanedial, contacting heptanedial with a polypeptide having the activity of a ω-transaminase to produce 7-aminoheptanal, and contacting 7-aminoheptanal with a polypeptide having the activity of a ω-transaminase to produce heptamethylenediamine, wherein
said polypeptide having the activity of a carboxylate reductase has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NOs: 7-12;
said polypeptide having the activity of a phosphopantetheine transferase enhancer has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 19 or SEQ ID NO: 20 or at least 85% sequence identity to the amino acid sequence of the gene products of griC and griD; and
said polypeptide having the activity of a ω-transaminase has at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 13-18.

18. The method of claim 5, further comprising enzymatically converting 7-aminoheptanoate to heptamethylenediamine by:
contacting 7-aminoheptanoate with a polypeptide having the activity of a carboxylate reductase optionally in combination with a polypeptide having the activity of a phosphopantetheine transferase enhancer to produce 7-aminoheptanal and contacting 7-aminoheptanal with a polypeptide having the activity of a ω-transaminase to produce heptamethylenediamine, wherein
said polypeptide having the activity of a carboxylate reductase has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NOs: 7-12;
said polypeptide having the activity of a phosphopantetheine transferase enhancer has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 19 or SEQ ID NO: 20 or at least 85% sequence identity to the amino acid sequence of the gene products of griC and griD; and
said polypeptide having the activity of a ω-transaminase has at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 13-18;

or contacting 7-aminoheptanoate with a polypeptide having the activity of a N-acetyltransferase to produce N7-acetyl-7-aminoheptanoate, contacting N7-acetyl-7-aminoheptanoate with a polypeptide having the activity of a carboxylate reductase optionally in combination with a polypeptide having the activity of a phosphopantetheine transferase enhancer to produce N7-acetyl-7-aminoheptanal, contacting N7-acetyl-7-aminoheptanal with a polypeptide having the activity of a ω-transaminase to produce N7-acetyl-1,7-diaminoheptane, and contacting N7-acetyl-1,7-diaminoheptane with a polypeptide having the activity of an acetylputrescine deacetylase to produce heptamethylenediamine, wherein
said polypeptide having the activity of a N-acetyltransferase is classified under EC 2.3.1.32;
said polypeptide having the activity of a carboxylate reductase has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NOs: 7-12;
said polypeptide having the activity of a phosphopantetheine transferase enhancer has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 19 or SEQ ID NO: 20 or at least 85% sequence identity to the amino acid sequence of the gene products of griC and griD;
said polypeptide having the activity of a ω-transaminase has at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 13-18; and
said polypeptide having the activity of an acetylputrescine deacetylase is classified under EC 3.5.1.62.

19. The method of claim 4, said method further comprising enzymatically converting pimelate semialdehyde to 7-hydroxyheptanoate by contacting 7-hydroxyheptanoate with a polypeptide having 6-hydroxyhexanoate dehydrogenase, 5-hydroxypentanoate dehydrogenase, 4-hydroxybutyrate dehydrogenase, or alcohol dehydrogenase activity, wherein
said polypeptide having the activity of a 6-hydroxyhexanoate dehydrogenase has at least 85% sequence identity to the amino acid sequence of a gene product of chnD;
said polypeptide having the activity of a 5-hydroxypentanoate dehydrogenase has at least 85% sequence identity to the amino acid sequence of a gene product of cpnD;
said polypeptide having the activity of a 4-hydroxybutyrate dehydrogenase has at least 85% sequence identity to the amino acid sequence of a gene product of a gbd; and
said polypeptide having the activity of an alcohol dehydrogenase has at least 85% sequence identity to the amino acid sequence of a gene product of hgdH, IdhA, yqhD, or YMR318C or the amino acid sequence of the protein having GenBank Accession No. CAA81612.1.

20. The method of claim 19, said method further comprising enzymatically converting 7-hydroxyheptanoate to 1,7-heptanediol by contacting 7-hydroxyheptanoate with a polypeptide having the activity of a carboxylate reductase optionally in combination with a polypeptide having the activity of a phosphopantetheine transferase enhancer to produce 7-hydroxyheptanal and contacting 7-hydroxyheptanal with a polypeptide having the activity of an alcohol dehydrogenase to produce 1,7-heptanediol, wherein
said polypeptide having the activity of a carboxylate reductase has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NOs: 7-12;
said polypeptide having the activity of a phosphopantetheine transferase enhancer has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 19 or SEQ ID NO: 20 or at least 85% sequence identity to the amino acid sequence of the gene products of griC and griD; and
said polypeptide having the activity of an alcohol dehydrogenase has at least 85% sequence identity to the amino acid sequence of a gene product of hgdH, IdhA, yqhD, or YMR318C or the amino acid sequence of the protein having GenBank Accession No. CAA81612.1.

21. The method of claim 19, said method further comprising enzymatically converting 7-hydroxyheptanoate to heptamethylenediamine by contacting 7-hydroxyheptanoate with a polypeptide having the activity of a carboxylate reductase optionally in combination with a polypeptide having the activity of a phosphopantetheine transferase enhancer to produce 7-hydroxyheptanal, contacting 7-hydroxyheptanal with a polypeptide having the activity of a ω-transaminase to produce 7-aminoheptanol, contacting 7-aminoheptanol with a polypeptide having the activity of an alcohol dehydrogenase to produce 7-aminoheptanal, and contacting 7-aminoheptanal with a polypeptide having the activity of a ω-transaminase to produce heptamethylenediamine, wherein
said polypeptide having the activity of a carboxylate reductase has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NOs: 7-12;
said polypeptide having the activity of a phosphopantetheine transferase enhancer has at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 19 or SEQ ID NO: 20 or at least 85% sequence identity to the amino acid sequence of the gene products of griC and griD;
said polypeptide having the activity of a ω-transaminase has at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 13-18; and
said polypeptide having the activity of an alcohol dehydrogenase has at least 85% sequence identity to the amino acid sequence of a gene product of hgdH, IdhA, yqhD, or YMR318C or the amino acid sequence of the protein having GenBank Accession No. CAA81612.1.

22. A method of shielding a carbon chain aliphatic backbone, functionalized with terminal carboxyl groups, in a recombinant host using at least one exogenous polypeptide expressed by said host, said method comprising:
enzymatically converting a n-carboxy-2-enoic acid to a n-carboxy-2-enoate methyl ester in said host by contacting said n-carboxy-2-enoic acid with a polypeptide having at least 85% sequence identity to any one of the amino acid sequences set forth in SEQ ID NOs: 1-3, wherein n+1 reflects the length of the carbon chain aliphatic backbone.

23. The method of claim 22, wherein the n-carboxy-2-enoic acid is 2(E) heptenedioic acid and the n-carboxy-2-enoate methyl ester is 2(E)-heptenedioate methyl ester.

24. A method of producing 2(E)-heptenedioyl-CoA methyl ester in a recombinant host using at least one exogenous polypeptide expressed by said host, said method comprising:
enzymatically converting 2(E)-heptenedioate to 2(E)-heptenedioate methyl ester by contacting 2(E)-heptenedioate with a polypeptide having at least 85% sequence identity to any one of the amino acid sequences set forth in SEQ ID NOs: 1-3;
enzymatically converting 2(E)-heptenedioate methyl ester to 2(E)-heptenedioyl-CoA methyl ester by contacting 2(E)-heptenedioate methyl ester with a polypeptide having at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 22 or SEQ ID NO: 23;
enzymatically converting 2(E)-heptenedioyl-CoA methyl ester to pimeloyl-CoA methyl ester by contacting 2(E)-heptenedioyl-CoA methyl ester with a polypeptide having at least 85% sequence identity to the amino acid sequence of SEQ ID NO: 26 or SEQ ID NO: 27; and
enzymatically converting pimeloyl-CoA methyl ester to pimeloyl-CoA by contacting pimeloyl-CoA methyl ester with a polypeptide having at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 6.

25. The method of claim 24, wherein 2(E)-heptenedioate is enzymatically produced from 2(E)-heptenedioyl-CoA by contacting 2(E)-heptenedioyl-CoA with a polypeptide having at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 4, 5, 21, 24, or 25.

26. The method of claim 24, wherein said method further comprises:
contacting pimeloyl-CoA with a polypeptide having at least 85% sequence identity to the amino acid sequence of the gene product of pduB or pduP to produce pimelate semialdehyde; or
contacting pimeloyl-CoA with a polypeptide having at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 4, 5, 21, 24, or 25 to produce pimelic acid and contacting pimelic acid with a polypeptide having at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 7-12 optionally in combination with a polypeptide having at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 19 or SEQ ID NO: 20 or at least 85% sequence identity to the amino acid sequence of the gene products of griC and griD to produce pimelate semialdehyde.

27. The method of claim 26, wherein said method further comprises enzymatically converting pimelate semialdehyde to 7-aminoheptanoate by contacting pimelate semialdehyde with a polypeptide having at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 13-18.

28. The method of claim 26, wherein said method further comprises enzymatically converting pimelate semialdehyde to heptamethylenediamine by contacting pimelate semialdehyde with a polypeptide having at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NOs: 7-12 optionally in combination with a polypeptide having at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 19 or SEQ ID NO: 20 or at least 85% sequence identity to the amino acid sequence of the gene products of griC and griD to produce heptanedial, contacting heptanedial with a polypeptide having at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 13-18 to produce 7-aminoheptanal, and contacting 7-aminoheptanal with a polypeptide having at least 85% sequence identity to the amino acid sequence set forth in any one of SEQ ID NOs: 13-18 to produce heptamethylenediamine.

29. The method of claim 26, wherein said method further comprises enzymatically converting pimelate semialdehyde to 7-hydroxyheptanoate by contacting 7-hydroxyheptanoate with a polypeptide having at least 85% sequence identity to the amino acid sequence of any one of a gene product of chnD, gbd, hgdH, IdhA, yqhD, or YMR318C or the amino acid sequence of the protein having GenBank Accession No. CAA81612.1.

30. The method of claim 29, wherein said method further comprises enzymatically converting 7-hydroxyheptanoate to 1,7-heptanediol by contacting 7-hydroxyheptanoate with a polypeptide having at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NOs: 7-12 optionally in combination with a polypeptide having at least 85% sequence identity to the amino acid sequence set forth in SEQ ID NO: 19 or SEQ ID NO: 20 or at least 85% sequence identity to the amino acid sequence of the gene products of gnrC and griD to produce 7-hydroxyheptanal and contacting 7-hydroxyheptanal with a polypeptide having at least 85% sequence identity to the amino acid sequence of a gene product of hgdH, IdhA, yqhD, or YMR318C or the amino acid sequence of the protein having GenBank Accession No. CAA81612.1 produce 1,7-heptanediol.