# Patent

## Title
Cysteine cross-linked structural peptides

## Abstract

Compositions and methods are provided using fusion peptides comprising at least one multi-functional solubility tag having an effective number of cross-linkable cysteines residues. The multi-functional peptidic solubility tags facilitate efficient fusion peptide production, easier downstream processing of the fusion peptide, and provide functional surface properties when coupled to a target material while the cross-linkable cysteines provide enhanced durability when binding the fusion peptide to a target material.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of pending U.S. patent application Ser. No. 13/528,201, filed Jun. 20, 2012, which claims priority to U.S. Provisional Patent Application No. 61/499,380, filed Jun. 21, 2011, both which are incorporated herein by reference in their entireties.


FIELD OF THE INVENTION
This invention relates to the field of recombinant production of fusion peptides comprising a multi-functional peptidic solubility tag coupled to a peptide of interest. The fusion peptide is engineered to comprise an effective number of cross-linkable cysteine residues dispersed within spacer elements to enhance surface binding durability. In addition to inducing inclusion body formation in an expression host, the solubility tag facilitates the ability to control fusion peptide solubility for more efficient downstream processing and provides surface functionalizing activity when associated with a target material.
BACKGROUND OF THE INVENTION
The efficient production of bioactive proteins and peptides has become a hallmark of the biomedical and industrial biochemical industry. Bioactive peptides and proteins are used as curative agents in a variety of diseases such as diabetes (insulin), viral infections and leukemia (interferon), diseases of the immune system (interleukins), and red blood cell deficiencies (erythropoietin) to name a few. Additionally, large quantities of proteins and peptides are needed for various industrial applications including, for example, the pulp and paper industries, textiles, food industries, personal care and cosmetics industries, sugar refining, wastewater treatment, production of alcoholic beverages and as catalysts for the generation of new pharmaceuticals.
In some cases commercially-useful proteins and peptides may be chemically synthesized or isolated from natural sources. However, these methods are often expensive, time consuming, and characterized by limited production capacity. Recombinant microbial production may be used to commercially produce the desired peptide/protein. However, recombinant production may also present a number of obstacles to be overcome in order to be a cost-effective. For example, peptides (and in particular short peptides) produced in a cellular environment are susceptible to degradation from the action of native cellular proteases. As such, purification and/or isolation of smaller peptides or proteins may be particularly difficult, resulting in poor yields and higher production costs.
One means to mitigate the above difficulties is the use of a genetic chimera for protein and peptide expression. A chimeric protein or “fusion protein” is a polypeptide comprising at least one portion of the desired protein product fused to at least one portion comprising a peptide tag. The peptide tag may be used to assist protein folding, assist post expression purification, protect the protein from the action of proteolytic enzymes, and/or assist the protein in passing through the cell membrane.
In many cases it is useful to express a peptide in an insoluble form, particularly when the peptide of interest is rather short, soluble, and/or subject to proteolytic degradation within the host cell. Production of the peptide in insoluble form both facilitates simple recovery and protects the peptide from the undesirable proteolytic degradation. One means to produce the peptide in insoluble form is to recombinantly produce the peptide as part of an insoluble fusion peptide by including within the fusion peptide at least one peptidic solubility tag (sometimes referred to as an “inclusion body tag”) that induces inclusion body formation. The fusion peptide is typically designed to include at least one cleavable peptide linker separating the inclusion body tag from the peptide of interest so that the peptide of interest can be subsequently recovered from the fusion peptide. The fusion peptide may be designed to include a plurality of inclusion body tags, cleavable peptide linkers, and regions encoding the peptide of interest.
Fusion proteins comprising a peptide solubility tag that facilitate the expression of insoluble proteins have been reported. The solubility tag of the chimeric or fusion protein is often large, increasing the likelihood that the fusion protein will be insoluble. Examples of large peptide solubility tags may include chloramphenicol acetyltransferase (Dykes et al., Eur. J. Biochem., 174:411 (1988), β-galactosidase (Schellenberger et al., Int. J. Peptide Protein Res., 41:326 (1993); Shen et al., Proc. Nat. Acad. Sci. USA 281:4627 (1984); and Kempe et al., Gene, 39:239 (1985)), glutathione-S-transferase (Ray et al., Bio/Technology, 11:64 (1993) and Hancock et al. (WO94/04688)), the N-terminus of L-ribulokinase (U.S. Pat. No. 5,206,154 and Lai et al., Antimicrob. Agents & Chemo., 37:1614 (1993), bacteriophage T4 gp55 protein (Gramm et al., Bio/Technology, 12:1017 (1994), bacterial ketosteroid isomerase protein (Kuliopulos et al., J. Am. Chem. Soc. 116:4599 (1994), ubiquitin (Pilon et al., Biotechnol. Prog. 13:374-79 (1997), bovine prochymosin (Naught et al., Biotechnol. Bioengin. 57:55-61 (1998), and bactericidal/permeability-increasing protein (“BPI”; U.S. Pat. No. 6,242,219 to Better et al.). The art is replete with specific examples of this technology, see for example U.S. Pat. No. 6,613,548, describing fusion protein of proteinaceous tag and a soluble protein and subsequent purification from cell lysate; U.S. Pat. No. 6,037,145, teaching a tag that protects the expressed chimeric protein from a specific protease; U.S. Pat. No. 5,648,244, teaching the synthesis of a fusion protein having a tag and a cleavable linker for facile purification of the desired protein; and U.S. Pat. Nos. 5,215,896; 5,302,526; 5,330,902; and 7,501,484, describing fusion tags containing amino acid compositions specifically designed to increase insolubility of the chimeric protein or peptide.
Shorter inclusion body tags have been developed from the Zea mays zein protein (U.S. Pat. No. 7,732,569), the Daucus carota cystatin (U.S. Pat. No. 7,662,913), an amyloid-like hypothetical protein from Caenorhabditis elegans (U.S. Pat. Nos. 7,427,656 and 7,795,382), and a ketosteroid isomerase-derived solubility tag modified to be more acid resistant (U.S. Pat. No. 7,829,311 to DeCarolis et al.). The use of a shorter inclusion body tag increases the yield of the target peptide produced within the recombinant host cell.
U.S. Pat. No. 7,951,559 to Alsop et al. discloses fusion proteins comprising cross-linkable inclusion body tags. After cleaving the recovered fusion protein, oxidative cross-linking is used to separate the inclusion body tag from the polypeptide of interest.
U.S. Pat. Nos. 7,678,883 and 7,794,979 to Cheng et al. disclose inclusion body tags derived from an 11 amino acid synthetic peptide (i.e., peptide “PII-2”; also known as peptide “DN1”) capable of self-assembly into β-sheet tapes, ribbons, fibrils, and fibers in water has been described (Aggeli et al., J. Amer. Chem. Soc., 125:9619-9628 (2003); Aggeli et al., PNAS, 98(21):11857-11862 (2001); Aggeli et al., Nature, 386:259-262 (1997); and Aggeli et al., J. Mater Chem, 7(7):1135-1145 (1997).
Fusion peptides comprising a solubility tag are typically subjected to a cleavage step to separate the solubility tag from the peptide of interest. Separating the solubility tag from the peptide of interest may be particularly desirable if the presence of the tag adversely impacts the properties of the peptide of interest. However, cleavage of the fusion peptide followed by one or more purification steps adds significant cost to the overall process.
One way to reduce the cost of producing a fusion peptide comprising a solubility tag is to use an inclusion body tag that does not need to be removed during downstream processing. Preferably, the “leave on” solubility tag is capable of providing additional functionality (beyond inclusion body formation) to the peptide of interest. Such multifunctional “leave on” solubility tags would significantly reduce the cost of manufacture and provide a higher value product
The use of multifunctional solubility tags (MSTs or LOTs) when preparing fusion peptides is described in co-owned and copending U.S. patent application Ser. No. 13/528,201. The multifunctional solubility tags described in Ser. No. 13/528,201 are (1) effective in preparing fusion proteins which accumulate in an insoluble form within the host cell (i.e., forming inclusion bodies), and (2) do not need to be cleaved from the fusion proteins prior to the intended use (i.e., the presence of the solubility tag in the fusion peptide/protein does not adversely impact the desired functionality of the polypeptide/protein of interest). In one embodiment, the MSTs provide the ability to control and/or enhance deposition and/or the binding properties of the fusion peptide for a desired target surface. However, the strength of binding between the engineered fusion peptide and the target surface may not be sufficient for certain commercial applications. As such, there remains a need to further enhance the binding properties between the fusion peptides and the target surface.
SUMMARY OF THE INVENTION
It has been discovered that the inclusion of cross-linkable cysteine residues within the spacer segments of certain multifunctional “leave on” solubility tags facilitates the use of oxidative cross-linking to further enhance the binding durability of the fusion peptide bound to the desired target surface. Methods and compositions are provided comprising a fusion peptide having a peptide of interest (POI) coupled to at least one multifunctional peptide solubility tag (also referred to as a “multifunctional inclusion body tag” or MST) that when present in the fusion protein (1) promotes inclusion body formation within the host cell, and (2) provides an additional functionality to the fusion protein comprising the peptide of interest; wherein the multifunctional solubility tag is engineered to include an effective number of cross-linkable cysteine residues within certain portions of the fusion construct. In one aspect, the additional functionality provided by the “leave on” solubility tag is a controllable and reversible solubility, enabling easier downstream processing, a binding functionality for a target material, or a combination of both. In a preferred aspect, the additional functionality of the “leave on” tag is a binding affinity for a first target material while the peptide of interest provide a binding functionality for a second target material, wherein the first and second target materials are not the same.
In one embodiment, a method is provided comprising:

    
    
        a) providing an aqueous solution comprising a population of fusion peptides, said fusion peptides having the general structure:
        MST-POI or
        POI-MST;
        wherein
        MST is a multifunctional solubility tag; and
        POI is a peptide of interest operably linked to the MST;
        wherein the multifunctional solubility tag (MST) has the general formula of:

SEQ ID NO: 1—Spacer−[[SEQ ID NO: 1]−[Spacer]m]n or  (i)

SEQ ID NO: 2—Spacer−[[SEQ ID NO: 2]−[Spacer]m]n;  (ii)

wherein

SEQ ID NO: 1 is Xaa1-Gln-[Xaa2]p-[Phe-Xaa3-Xaa4-Xaa5]s-Phe-Xaa6-[Xaa7]q-[Gln]r; and

SEQ ID NO: 2 is Xaa1-Gln-Xaa8-[Xaa4-Xaa8]s-Phe-[Glu-Gln-Gln]r;

        wherein
        Xaa1=Gln or His;
        Xaa2=Gln, Arg, His, or Lys;
        Xaa3=Gln, His, Lys, Arg, or Glu;
        Xaa4=Trp or Phe;
        Xaa5=Gln, His, Lys, Arg or Glu;
        Xaa6=Glu, Gln, or Arg;
        Xaa7=Gln or Lys;
        Xaa8=Asp, Glu, Gln, His, Lys, or Arg;
        p, q, and r are independently 0 or 1;
        s is an integer ranging from 1 to 5;
        n is an integer ranging from 2 to 10;
        m=n or n−1; and
        Spacer=a peptide linker ranging from 1 to 100 amino acids in length; wherein said spacer comprises at least one cross-linkable cysteine residue; wherein the aqueous solution has a pH of at least 10 and wherein the at least one cross-linkable cysteine residue is reduced;
        b) contacting the aqueous solution of (a) with a first target material whereby a mixture if formed;
        c) altering the pH of the mixture of (b) whereby at least a portion of the population of fusion peptides non-covalently associate with the first target material, forming one or more fusion peptide-first target material complexes; wherein the association between the fusion peptides and the first target material is dependent upon, or enhanced by, the presence of the multifunctional solubility tag;
        d) subjecting the fusion peptide-first target material complexes of (c) to oxidizing conditions whereby cysteine residues cross-link; and
        e) optionally recovering the product of step (d).
    
    


In another embodiment, a method is provided comprising:

    
    
        a) providing a host cell comprising an expressible genetic construct encoding an insoluble fusion peptide comprising at least one first portion and at least one second portion, wherein said first portion comprises a multifunctional solubility tag (MST) and said second portion comprises a peptide of interest (POI); wherein the multifunctional solubility tag (MST) has the general formula of:

SEQ ID NO: 1—Spacer−[[SEQ ID NO: 1]−[Spacer]m]n or  (i)

SEQ ID NO: 2—Spacer−[[SEQ ID NO: 2]−[Spacer]m]n;  (ii)

        wherein

SEQ ID NO: 1 is Xaa1-Gln-[Xaa2]p-[Phe-Xaa3-Xaa4-Xaa5]s-Phe-Xaa6-[Xaa7]q-[Gln]r; and

SEQ ID NO: 2 is Xaa1-Gln-Xaa8-[Xaa4-Xaa8]s-Phe-[Glu-Gln-Gln]r;

        wherein
        Xaa1=Gln or His;
        Xaa2=Gln, Arg, His, or Lys;
        Xaa3=Gln, His, Lys, Arg, or Glu;
        Xaa4=Trp or Phe;
        Xaa5=Gln, His, Lys, Arg or Glu;
        Xaa6=Glu, Gln, or Arg;
        Xaa7=Gln or Lys;
        Xaa8=Asp, Glu, Gln, His, Lys, or Arg;
        p, q, and r are independently 0 or 1;
        s is an integer ranging from 1 to 5;
        n is an integer ranging from 2 to 10;
        m=n or n−1; and
        Spacer=a peptide linker ranging from 1 to 100 amino acids in length; wherein said spacer comprises at least one cross-linkable cysteine residue;
        b) growing the host cell under conditions whereby the insoluble fusion peptide is produced within the host cell in the form of at least one inclusion body;
        c) recovering the insoluble fusion peptide from the host cell;
        d) subjecting the recovered insoluble fusion peptide of (c) to aqueous reducing conditions have a pH of at least 10 for a period of time sufficient to solubilize the insoluble fusion peptide and reduce cross-linkable cysteine residues; whereby an aqueous solution comprising a population of reduced fusion peptides is produced;
        e) contacting the aqueous solution comprising the population of reduced fusion peptides of (d) with a first target material whereby a mixture is formed;
        f) altering the pH of the mixture of (e) whereby at least a portion of the population of reduced fusion peptides non-covalently associates with the first target material, forming fusion peptide-first target material complexes; wherein the association between the fusion peptides and the first target material is dependent upon, or enhanced by, the presence of the multifunctional solubility tag;
        g) subjecting the fusion peptide-first target material complexes of (f) to oxidizing conditions whereby the cysteine residues cross-link; and
        h) optionally recovering the product of step (g).
    
    


In a preferred embodiment, the host cell is a microbial host cell engineered to express the genetic construct encoding the chimeric fusion peptide.
In another embodiment, multifunctional solubility tags are provided comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 75, 77, 499, 500, 501, 502, 503, 504, and 505.
In another embodiment, multifunctional solubility tags are provided comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 499, 500, 501, 502, 503, 504, and 505.
In another embodiment, multifunctional solubility tags are provided comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 75 and 77.
In another embodiment, fusion peptides comprising the above multifunctional solubility tags are also provided.
In another embodiment, a composition comprising a particle coupled to at least one of the present fusion peptides is also provided; wherein the particle comprises an average particle size of 3 nm to 10 μm as measured by a light scattering method, is also provided.
In another embodiment, a personal care product comprising at least one of the present fusion peptides or the above composition is also provided.
The present fusion peptides may also be used in affinity media. In a further embodiment, affinity media is provided having a solid support comprising an effective amount of a fusion peptide (i.e., as a coating, layer or embedded within and/or on the affinity media), said fusion peptide having a first portion and a second portion, wherein said first portion comprises a multifunctional solubility tag (MST) that is bound to the solid support and said second portion of the fusion peptide comprising an affinity for a target material; wherein the multifunctional solubility tag has the general formula:

SEQ ID NO: 1—Spacer−[[SEQ ID NO: 1]−[Spacer]m]n or  a)

SEQ ID NO: 2—Spacer−[[SEQ ID NO: 2]−[Spacer]m]n;  b)

wherein

SEQ ID NO: 1 is Xaa1-Gln-[Xaa2]p-[Phe-Xaa3-Xaa4-Xaa5]s-Phe-Xaa6-[Xaa7]q-[Gln]r; and

SEQ ID NO: 2 is Xaa1-Gln-Xaa8-[Xaa4-Xaa8]s-Phe-[Glu-Gln-Gln]r;

wherein

    
    
        Xaa1=Gln or His;
        Xaa2=Gln, Arg, His, or Lys;
        Xaa3=Gln, His, Lys, Arg, or Glu;
        Xaa4=Trp or Phe;
        Xaa5=Gln, His, Lys, Arg or Glu;
        Xaa6=Glu, Gln, or Arg;
        Xaa7=Gln or Lys;
        Xaa8=Asp, Glu, Gln, His, Lys, or Arg;
        p, q, and r are independently 0 or 1;
        s is an integer ranging from 1 to 5;
        n is an integer ranging from 1 to 10;
        m=n or n−1; and
        Spacer=a peptide linker ranging from 1 to 100 amino acids in length, wherein said spacer comprises at least one cross-linkable cysteine residue.
    
    


In a further aspect, the affinity media comprises a solid support comprising a material selected from the group consisting of a pigment, a plant tissue, a polymer, polystyrene, polyethylene, polypropylene, polytetrafluoroethylene, polyester, polyvinyl chloride, poly(methyl methacrylate), polyethersulfone, polyimide, polyamide, aramids, poly para-phenylene terephthalamide, poly meta-phenylene terephthalamide, poly urethanes, protein fibrils, polysaccharides, cellulose, starch, chitin, minerals, silica, silicates, micas, titanium dioxide, tungsten carbide, alumina, iron oxides, clays, metals, gold, silver, carbon, carbon black, graphite and carbon nanotubes. In a further aspect, the solid support is in the form of a resin, a membrane, a filter, a bead, a fiber, a foam, a film or any combination thereof.
The affinity media comprising at least one of the present fusion peptides may be used in a method to obtain a material from an aqueous matrix. As such, a method is provided comprising:
a) providing an aqueous matrix comprising a target material to be obtained from the aqueous matrix; and
b) contacting the aqueous matrix with the affinity media described above whereby the target material binds to the fusion protein. In a preferred aspect, the above method further comprises step (c), eluting the bound target material from the affinity media.
In a preferred aspect, the aqueous matrix used in the method to obtain a target material is a biological fluid, a waste stream, a waste stream from mining operations, an environmental sample, a fermentation medium, an aqueous sample comprising fermentation biomass.
In another embodiment, a pharmaceutical, agricultural, or cosmetic composition is provided comprising at least one of the present fusion peptides and/or one of the present composition described above.
In another embodiment, a biomedical or tissue engineering composition is provided comprising at least one of the present fusion peptides and/or the present composition described above.



BRIEF DESCRIPTION OF THE FIGURES
FIG. 1. The oxidized sample exhibits higher acid resistance than the reduced sample. FIG. 1A (gel image) shows the results of the oxidized sample, FIG. 1B (gel image) that of the reduced sample. Lane 1 shows the amount of protein bound to the initial adduct prior to the pH shift, lane 2 the corresponding amount of protein in the supernatant. Lanes 5 and 6, respectively, show the equivalent results found for the reduced sample. Lane 3 shows to the amount of protein released from the pigments upon low pH challenge of the oxidized sample. Lane 4 shows the amount of protein that remained associated with the pigments after low pH challenge of the oxidized sample. Lane 7 shows the amount of protein released from the pigment from the reduced sample. Lane 8 shows the amount of protein that remained bound post challenge on the pigment under the reducing conditions.
FIG. 2. The amount of protein remaining on pigments for each peptide under oxidizing conditions, either including a low pH challenge or not. The “+” or “−” symbols over the lanes indicates the presence or absence of added hydrochloric acid (low pH challenge). The names of the fusion constructs, with and without cross-likable cysteine residues (i.e., “cys”) are listed to the left of each gel image.
FIG. 3. Oxidized sample exhibits higher acid resistance than the reduced sample to a detergent challenge. Lanes are numbered 1 through 8. FIG. 3A (gel image) shows the results of the oxidized sample (pre- and post-challenge); FIG. 3B (gel image) is that of the reduced sample (pre- and post-challenge). Lane 1 is the amount of protein bound to the initial adduct prior to the detergent challenge. Lane 2 is the corresponding amount of protein in the supernatant. Lane 5 is the amount of protein bound to the pigment, pre-challenge from the reduced sample. Lane 6 is the amount of protein bound to the pigment post challenge for the reduced sample. Lane 4 is the amount of post-challenge released protein from the oxidized sample. Lane 8 is the amount of post-challenge released protein from the reduced sample.
FIG. 4. Peptides containing cross-linkable cysteine (“cys”) residues in their sequence show higher resistance to detergent challenge than the equivalent samples without cysteine residues under oxidizing conditions. The names of the fusion constructs, with and without cross-likable cysteine residues (i.e., “cys”) are listed to the left of each gel image. The “+” and “−” symbols are used to show samples with or without added detergent challenge (“SLES”—sodium lauryl ether sulfate).
FIG. 5: Oxidized protein exhibits high acid resistance with three different types of pigments. The results for oxidized fusion peptide sample IBT331-HC263 bound to different type of pigments to pre- and post-challenge (acid challenge). The results for a 0.25% suspensions of silica-coated red iron oxide (“50B”), red iron oxide (“RIO”, and silica particles (“silica”) are shown.



BRIEF DESCRIPTION OF THE BIOLOGICAL SEQUENCES
The following sequences comply with 37 C.F.R. 1.821-1.825 (“Requirements for Patent Applications Containing Nucleotide Sequences and/or Amino Acid Sequence Disclosures—the Sequence Rules”) and are consistent with World Intellectual Property Organization (WIPO) Standard ST.25 (1998) and the sequence listing requirements of the EPC and PCT (Rules 5.2 and 49.5(a bis), and Section 208 and Annex C of the Administrative Instructions). The symbols and format used for nucleotide and amino acid sequence data comply with the rules set forth in 37 C.F.R. §1.822.
SEQ ID NO: 1 is the amino acid sequence a structural formula for multifunctional inclusion body tags.
SEQ ID NO: 2 is the amino acid sequence a structural formula for multifunctional inclusion body tags.
SEQ ID NO: 3 is the nucleic acid sequence of a polynucleotide encoding IBT187.1.
SEQ ID NO: 4 is the amino acid sequence of IBT187.1.
SEQ ID NO: 5 is the nucleic acid sequence encoding the peptide of interest HC263.
SEQ ID NO: 6 is the amino acid sequence of the peptide of interest HC263.
SEQ ID NO: 7 is the nucleic acid sequence encoding fusion peptide IBT187.HC263.
SEQ ID NO: 8 is the amino acid sequence of fusion peptide IBT187.HC263.
SEQ ID NO: 9 is the nucleic acid sequence encoding fusion peptide IBT187.H2-TonB.G3.
SEQ ID NO: 10 is the amino acid sequence of fusion peptide IBT187.H2-TonB.G3.
SEQ ID NO: 11 is the nucleic acid sequence of a polynucleotide encoding IBT233.
SEQ ID NO: 12 is the nucleic acid sequence encoding fusion peptide IBT233.HC263.
SEQ ID NO: 13 is the amino acid sequence of fusion peptide IBT233.HC263.
SEQ ID NO: 14 is the amino acid sequence of IBT139.
SEQ ID NO: 15 is the amino acid sequence of IBT201.
SEQ ID NO: 16 is the amino acid sequence of IBT202.
SEQ ID NO: 17 is the amino acid sequence of IBT203.
SEQ ID NO: 18 is the amino acid sequence of IBT204.
SEQ ID NO: 19 is the amino acid sequence of IBT205.
SEQ ID NO: 20 is the amino acid sequence of IBT206.
SEQ ID NO: 21 is the amino acid sequence of IBT207.
SEQ ID NO: 22 is the amino acid sequence of IBT208.
SEQ ID NO: 23 is the amino acid sequence of IBT209.
SEQ ID NO: 24 is the amino acid sequence of IBT210.
SEQ ID NO: 25 is the amino acid sequence of IBT212.
SEQ ID NO: 26 is the amino acid sequence of IBT214.
SEQ ID NO: 27 is the amino acid sequence of IBT216.
SEQ ID NO: 28 is the amino acid sequence of IBT218.
SEQ ID NO: 29 is the amino acid sequence of IBT220.
SEQ ID NO: 30 is the amino acid sequence of IBT222.
SEQ ID NO: 31 is the amino acid sequence of IBT223.
SEQ ID NO: 32 is the amino acid sequence of IBT224.
SEQ ID NO: 33 is the amino acid sequence of IBT225.
SEQ ID NO: 34 is the amino acid sequence of IBT229.
SEQ ID NO: 35 is the amino acid sequence of IBT230.
SEQ ID NO: 36 is the amino acid sequence of IBT232.
SEQ ID NO: 37 is the amino acid sequence of IBT233.
SEQ ID NO: 38 is the amino acid sequence of IBT239.
SEQ ID NO: 39 is the amino acid sequence of IBT241.
SEQ ID NO: 40 is the amino acid sequence of IBT242.
SEQ ID NO: 41 is the amino acid sequence of IBT247.
SEQ ID NO: 42 is the amino acid sequence of IBT248.
SEQ ID NO: 43 is the amino acid sequence of IBT249.
SEQ ID NO: 44 is the amino acid sequence of IBT254.
SEQ ID NO: 45 is the amino acid sequence of IBT255.
SEQ ID NO: 46 is the amino acid sequence of IBT258.
SEQ ID NO: 47 is the amino acid sequence of IBT259.
SEQ ID NO: 48 is the amino acid sequence of IBT260.
SEQ ID NO: 49 is the amino acid sequence of IBT261.
SEQ ID NO: 50 is the amino acid sequence of IBT262.
SEQ ID NO: 51 is the amino acid sequence of IBT263.
SEQ ID NO: 52 is the amino acid sequence of IBT282.
SEQ ID NO: 53 is the amino acid sequence of IBT283.
SEQ ID NO: 54 is the amino acid sequence of IBT284.
SEQ ID NO: 55 is the amino acid sequence of IBT287.
SEQ ID NO: 56 is the amino acid sequence of IBT289.
SEQ ID NO: 57 is the amino acid sequence of IBT290.
SEQ ID NO: 58 is the amino acid sequence of IBT294.
SEQ ID NO: 59 is the amino acid sequence of IBT295.
SEQ ID NO: 60 is the amino acid sequence of IBT297.
SEQ ID NO: 61 is the amino acid sequence of IBT298.
SEQ ID NO: 62 is the amino acid sequence of IBT299.
SEQ ID NO: 63 is the amino acid sequence of IBT310.
SEQ ID NO: 64 is the amino acid sequence of IBT311.
SEQ ID NO: 65 is the amino acid sequence of IBT312.
SEQ ID NO: 66 is the amino acid sequence of IBT313.
SEQ ID NO: 67 is the amino acid sequence of IBT314.
SEQ ID NO: 68 is the amino acid sequence of IBT315.
SEQ ID NO: 69 is the amino acid sequence of IBT316.
SEQ ID NO: 70 is the amino acid sequence of IBT317.
SEQ ID NO: 71 is the amino acid sequence of IBT320.
SEQ ID NO: 72 is the amino acid sequence of IBT321.
SEQ ID NO: 73 is the amino acid sequence of IBT326.
SEQ ID NO: 74 is the amino acid sequence of IBT327.
SEQ ID NO: 75 is the amino acid sequence of IBT332.
SEQ ID NO: 76 is the amino acid sequence of IBT334.
SEQ ID NO: 77 is the amino acid sequence of IBT340.
SEQ ID NO: 78 is the nucleic acid sequence of plasmid pLR548.
SEQ ID NO: 79 is the nucleic acid sequence of plasmid pLD001.233.
SEQ ID NOs: 80-104 are the amino acid sequences of core motifs found in at least one of the multifunctional inclusion body tags.
SEQ ID NOs: 105-392 are the amino acid sequences of exemplary peptides that to bind at least one body surface including hair (SEQ ID NOs: 105-231), skin (SEQ ID NOs: 227-279), nail (SEQ ID NOs: 280-281), and tooth (SEQ ID NOs: 282-392).
SEQ ID NOs: 393-421 are the amino acid sequences of exemplary antimicrobial peptides.
SEQ ID NOs: 422-446 are the amino acid sequences of exemplary pigment binding peptides.
SEQ ID NOs: 447-452 are exemplary cellulose-binding peptides.
SEQ ID NOs: 453-479 are the amino acid sequences of exemplary polymer binding peptides. Specifically, SEQ ID NO: 453 binds to poly(ethylene terephthalate), SEQ ID NOs: 454-464 bind to poly(methyl methacrylate), SEQ ID NOs: 465-470 bind to Nylon, and SEQ ID NOs: 471-479 bind to poly(tetrafluoroethylene).
SEQ ID NOs: 480-495 are the amino acid sequences of exemplary clay binding peptides.
SEQ ID NO: 496 is the amino acid sequence of “AuBD”, a peptide having affinity for gold.
SEQ ID NO: 497 is the amino acid sequence of fusion peptide IBT255.AuBD.
SEQ ID NO: 498 is the amino acid sequence of synthetic peptide HC353 (U.S. Patent Application Publication No. 2010-0158837; hereby incorporated by reference).
SEQ ID NO: 499 is the amino acid sequence of IBT331
SEQ ID NO: 500 is the amino acid sequence of IBT333
SEQ ID NO: 501 is the amino acid sequence of IBT341
SEQ ID NO: 502 is the amino acid sequence of IBT185
SEQ ID NO: 503 is the amino acid sequence of IBT186
SEQ ID NO: 504 is the amino acid sequence of IBT292
SEQ ID NO: 505 is the amino acid sequence of IBT293
SEQ ID NO: 506 is the amino acid sequence of IBT255-HC263.
SEQ ID NO: 507 is the amino acid sequence of IBT340-HC263.
SEQ ID NO: 508 is the amino acid sequence of IBT310-HC263.
SEQ ID NO: 509 is the amino acid sequence of IBT331-HC263.
DETAILED DESCRIPTION OF THE INVENTION
Compositions and methods directed to the use of a multifunctional solubility tag comprising an effective number of cross-linkable cysteine residues as a component of fusion peptide/protein are provided herein, wherein the presence of the multifunctional solubility tag having an effective number of cross-linkable cysteine residues in the fusion peptide facilitates:
(i) producing the fusion peptide in an insoluble form (i.e., induces inclusion body formation) within a recombinant host cell;
(ii) controlling fusion peptide solubility (once recovered from the recombinant host cell) upon modulation of physio-chemical conditions;
(iii) providing new or enhanced surface active properties;
(iv) increasing the overall efficiency of production; and
(v) enhances the binding durability of the fusion peptide non-covalently bound to a target surface (i.e., the binding durability of fusion peptide-target material adducts) upon oxidative cross-linking.
In this disclosure, a number of terms and abbreviations are used. The following definitions apply unless specifically stated otherwise. Unless otherwise noted, all U.S. patents and U.S. patent applications referenced herein are incorporated by reference in their entirety.
As used herein, the articles “a”, “an”, and “the” preceding an element or component of the invention are intended to be nonrestrictive regarding the number of instances (i.e., occurrences) of the element or component. Therefore “a”, “an” and “the” should be read to include one or at least one, and the singular word form of the element or component also includes the plural unless the number is obviously meant to be singular.
The term “comprising” means the presence of the stated features, integers, steps, or components as referred to in the claims, but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. The term “comprising” is intended to include embodiments encompassed by the terms “consisting essentially of” and “consisting of”. Similarly, the term “consisting essentially of” is intended to include embodiments encompassed by the term “consisting of”.
As used herein, the term “about” modifying the quantity of an ingredient or reactant employed refers to variation in the numerical quantity that can occur, for example, through typical measuring and liquid handling procedures used for making concentrates or use solutions in the real world; through inadvertent error in these procedures; through differences in the manufacture, source, or purity of the ingredients employed to make the compositions or carry out the methods; and the like. The term “about” also encompasses amounts that differ due to different equilibrium conditions for a composition resulting from a particular initial mixture. Whether or not modified by the term “about”, the claims include equivalents to the quantities.
Where present, all ranges are inclusive and combinable. For example, when a range of “1 to 5” is recited, the recited range should be construed as including ranges “1 to 4”, “1 to 3”, “1-2”, “1-2 & 4-5”, “1-3 & 5”, and the like.
As used herein, an “inclusion body” is an intracellular deposit comprising aggregated protein found in the cytoplasm of a cell. A peptide of interest that is typically soluble under the normal physiological conditions within the host cell and/or cell lysates can be fused to one or more of the multifunctional inclusion body tags to facilitate formation of an insoluble fusion protein. In another embodiment, the peptide of interest may be partially insoluble in the host cell, but produced at relatively lows levels where significant inclusion body formation does not occur. As such, the formation of inclusion bodies will increase peptide production. In a further embodiment, fusion of the peptide of interest to one or more multifunctional inclusion body tags increases the amount of protein produced in the host cell. Formation of the inclusion body facilitates simple and efficient purification of the fusion peptide from the cell lysate using techniques well known in the art such as centrifugation and filtration.
As used herein, the term “effective amount” will refer to the amount of a given condition, a composition or a combination thereof necessary to obtain a desired effect (e.g., cross-linkable cysteine residues necessary to achieve the benefits of oxidative cross-linking, etc.).
As used herein, the term “effective number of cysteine residues” is used to describe the number of cysteine residues required to obtain the desired effect (i.e. the ability to use oxidative cross-linking to cross-link cysteine residues located within the spacer component of the present multifunctional solubility tags). It is well within the skill of one in the art to vary the number and/or location of the cysteine residues within the spacer/linker regions to practice the present process. In one embodiment, the effective number of cysteine residues is at least 1 within a multifunctional solubility tag (for example, cross-linking between different multifunctional solubility tags within a population of fusion proteins having one or more multifunctional solubility tags), preferably at least 2, more preferably at least 3, and even more preferably at least 4. In another embodiment, the effective number of cysteine residues is 3 to about 20, preferably 3 to about 10, more preferably 3 to about 6, more preferably 3 to about 5, and most preferably 4 to 5 cross-linkable cysteine residues.
As used herein, the terms “inclusion body tag” and “solubility tag” will be abbreviated “IBT” and will refer a peptide/polypeptide that facilitates formation of inclusion bodies when fused to a peptide of interest. The peptide of interest is typically soluble within the host cell and/or host cell lysate when not fused to an inclusion body tag. Fusion of the peptide of interest to the inclusion body tag produces a fusion protein that agglomerates into intracellular bodies (inclusion bodies) within the host cell.
As used herein, the terms “multifunctional tag”, “multifunctional solubility tag”, “multifunctional inclusion body tag”, “MST”, “leave-on tag”, and “LOT” will refer to an inclusion body tag having at least one beneficial functionality beyond inclusion body formation when present in a fusion peptide and wherein the present multifunctional tags have been modified to include at least once cross-linkable cysteine residue within the tag. In a preferred aspect, the cross-linkable cysteine residues are incorporated into the spacer elements between the functional core motifs of the MST(s). To be clear, the multifunctional solubility tag (MST), or sometimes referred to herein simply as an “inclusion body tag” (IBT), is not removed from the fusion protein and provides additional functionality; wherein it also provides oxidative cross-linking capability through the inclusion of an effective number of cross-linkable cysteines within linker/spacer elements in the MST). The presence of the multifunctional solubility tag in the fusion protein provides the ability to control solubility of the fusion peptide under different physio-chemical conditions. In another embodiment, the presence of the multifunctional solubility tag in the fusion protein provides new or enhanced surface active properties. For example, the MST may provide a binding affinity for a first target material or may enhance the binding properties of the peptide of interest (POI) for a first target material. In another embodiment, the MST has affinity for a first target material while the peptide of interest (POI) portion of the fusion peptide has affinity for a second target material. As such, the fusion peptide may be used as a peptidic bridge to couple a first target material to a second target material, wherein the first and second target materials are compositionally different.
As used herein, the term “spacer” (which may be italicized when used in general formulas) will refer to a peptide within the present inclusion body tags used to separate the core motif sequences (SEQ ID NOs: 1, 2, and 80-101). At least one spacer element will be present within each multifunctional solubility tag (i.e., 2 or more core motif sequences separated by at least one peptidic spacer). At least one spacer within the fusion peptide/protein will contain at least one cross-linkable cysteine residue. In a preferred aspect, a plurality of spacers are used comprising one or more cross-linkable cysteine residues. In a further preferred aspect, each spacer element will contain at least one cross-linkable cysteine residue. In one embodiment, the spacer is 1-100 amino acids in length, preferably 3 to 60 amino acids in length, and most preferably 3 to 30 amino acids in length and is comprised of any naturally occurring L-amino acids. In a further embodiment, the “spacer” is comprised of (in addition to at least one cross-linkable cysteine residue) one or more L-amino acids selected from the group consisting of proline, glycine, arginine, asparagine, glutamic acid, glutamine, serine, tyrosine, tryptophan, alanine, leucine, isoleucine, threonine, histidine, lysine, aspartic acid, and combinations thereof. The multifunctional solubility tag includes at least one spacer, preferably a plurality of spacers, to promote oxidative cross-linking. In one embodiment, the MST comprises 1 to 10 spacer elements, preferably 1 to 5, and most preferably 1 to 3 spacer elements. In a preferred aspect, a plurality of spacer elements are present within the multifunctional solubility tag, wherein each spacer preferably comprises an effective number of cross-linkable cysteine residues.
As used herein, the term “peptide of interest” or “POI” is any peptide that provides a defined desired functionality (that by itself is distinct from the functionality of the multifunctional inclusion body tag), such as a binding affinity for a target material, surface or a specific molecule; a biological activity such as a growth factor or an antimicrobial; a physical modification of a surface to provide charge, hydrophobicity, chelation, dispersion, optical properties such as refractive index, color, UV protection or fluorescence or conditioning agent, and the ability to self-assemble in macromolecular structures. The peptide of interest may comprise one or more distinct surface binding domains. The peptide of interest is soluble and/or difficult to accumulate within the microbial host cell when not produced in the form of a fusion peptide comprising at least one of the present multifunctional inclusion body tags.
As used herein, the terms “fusion protein”, “fusion peptide”, “chimeric protein”, and “chimeric peptide” will be used interchangeably and will refer to a polymer of amino acids (peptide, oligopeptide, polypeptide, or protein) comprising at least two portions, each portion comprising distinct function(s). The present fusion peptides comprise at least one multifunctional solubility tag and at least one peptide of interest, wherein the presence of the multi-functional inclusion body tag provides additional functionality (beyond inclusion body formation) to the fusion peptide. Means to prepare peptides synthetically at small scale are well known in the art (see, for example, Stewart et al., Solid Phase Peptide Synthesis, Pierce Chemical Co., Rockford, Ill., 1984; Bodanszky, Principles of Peptide Synthesis, Springer-Verlag, New York, 1984; and Pennington et al., Peptide Synthesis Protocols, Humana Press, Totowa, N.J., 1994). The various components of the fusion peptides described herein can be combined using carbodiimide coupling agents (see for example, Hermanson, Greg T., Bioconjugate Techniques, Academic Press, New York (1996)), diacid chlorides, diisocyanates and other difunctional coupling reagents that are reactive to terminal amine and/or carboxylic acid groups on the peptides. However, chemical synthesis is often limited to peptides of less than about 50 amino acids length due to cost and/or impurities. In a preferred embodiment, the biological molecules described herein are prepared using standard recombinant DNA and molecular cloning techniques.
As used herein, the term “altering the physio-chemical conditions” will refer to making alterations to the pH, temperature, ionic composition, ionic strength of the aqueous matrix, and any combination thereof that facilitates controlled solubility of the fusion peptide comprising the multifunctional inclusion body tag. Under normal physiological conditions within the recombinant microbial host cell (typically an intracellular pH of about 6.5- about 8.0, preferably about 7.5 to about 8.0 for most neutrophiles) the multifunctional inclusion body tag induces inclusion body formation. The fusion peptide may be subjected to altered physio-chemical conditions (typically after the fusion peptide has been recovered from the host cell) to control the solubility, wherein the presence of the leave-on tag alters the solubility profile of the fusion peptide. The physio-chemical conditions may be altered one or more times to dissolve or precipitate the fusion peptide. In one embodiment, solubilized fusion peptide (in the presence of a target material) may be exposed to physio-chemical conditions that induces or enhances deposition/binding of the fusion peptide to the surface of the target material. Physico-chemical conditions that can be modified to promote the solubility or the insolubility of a fusion peptide (typically once recovered from the cell) may include pH, medium conductivity, salts, metal ions, polyvalent ions, chaotropes, surfactants, solvents, fusion peptide concentration, rheology modifiers, thickeners and temperature.
As used herein, the term “medium” may mean fermentation medium or a suspension medium. The fermentation medium is the medium which supports the growth of fusion peptide-producing cells. The medium is typically aqueous but may also include a water-oil emulsion. As used herein, the term “aqueous medium” refers to a medium comprising water. The solubility state of the fusion peptides recovered from the host cell is controlled by altering the physio-chemical conditions within an aqueous medium comprising the fusion peptide. Different sets of physio-chemical conditions may used and may be generally separated into three general categories: (1) a set of conditions that promotes solubility, (2) a set of conditions that promotes insolubility, and (3) a set of conditions that may promote or enhance deposition of the fusion peptide to a target material surface (i.e., the target material is contacted with a medium comprising the fusion peptide).
As used herein, the term “benefit agent” refers to a material that promotes or enhances a useful advantage, a favorable/desirable effect or benefit. The benefit agent may be a fusion peptide or a molecule or a material associated with (or coupled to) a portion of the fusion peptide. Examples of benefits agents may include, but are not limited to conditioners, pigments, dyes, fragrances, whitening agents, bleaching agents, enzymes, pharmaceutical agents (e.g., targeted delivery of cancer treatment agents), diagnostic/labeling agents, ultraviolet light blocking agents (i.e., active agents in sunscreen protectants), affinity media, particles, and antimicrobial agents (e.g., antimicrobial peptides), to name a few. The benefit agent may be a particulate benefit agent. In one embodiment, the particulate (benefit agent) or the fusion peptide-particulate benefit agent complex may have an average particle size of 3 nm to 10 μm as measured by a light scattering method. It will be understood by those skilled in the art that the “particle size” referenced herein will refer to the particle size measurements obtained using a light scattering methods such as laser diffraction (see ISO 13320-1:1996; International Organization for Standards, Geneva, Switzerland) and/or dynamic light scattering (see ISO 13321:1996) methodologies, both of which are known in the art. Exemplary systems are available from Malvern Instruments Ltd. Worcestershire, United Kingdom.
As used herein, the term “target material” will refer to a material that receives or delivers a beneficial or desired property upon the presence of the fusion peptide. In one embodiment, the fusion peptide has affinity for a target material wherein the binding functionality is dependent upon the presence of the multifunctional inclusion boy tag (MST), the peptide of interest (POI), or a combination of the MST and POI. In one embodiment, the presence of the MST enhances the binding affinity of a POI having affinity for a target material. In another embodiment, the MST has affinity for a target surface and the portion of the fusion peptide comprising the peptide of interest is a benefit agent, such as a conditioning agent or antimicrobial agent (e.g., antimicrobial peptide).
The target material(s) may vary and may include in certain embodiments films, particles, and coated particles. In one embodiment, the target material may include a pigment (such as lakes, insoluble organic pigment, insoluble inorganic pigment), a body tissue suitable for cosmetic personal care products (e.g., hair, skin, nail, teeth and other oral cavity tissues), a body tissue for medical or veterinary applications, a plant tissue (e.g., seeds, leaves, stems, flowers, fruit, etc.), a polymer (such as polystyrene, polyethylene, polypropylene, polytetrafluoroethylene, polyester, polyvinyl chloride, poly(methyl methacrylate), polyethersulfone, polyimide, polyamide, aramids (e.g., poly para-phenylene terephthalamide; “KEVLAR®”, poly meta-phenylene terephthalamide; “NOMEX®”, poly urethanes), and polysaccharides (e.g. cellulose, cellulosic materials, starch, chitin)), minerals (e.g. silica, silicates, micas, titanium dioxide, alumina, iron oxides, clays), and metals (e.g., gold, silver), carbon surfaces such as carbon black, graphite and carbon nanotubes, to name a few.
As used herein, the “core motifs” within the multifunctional solubility tags are portions of the multifunctional solubility tag that are used to alter solubility. The multifunctional solubility tags are designed to include at least two core motifs separated by at least one spacer element. The core motif sequences are provided herein by the formulas defined by SEQ ID NO: 1 and SEQ ID NO: 2. Specific examples of core motifs are provided herein as SEQ ID NOs: 80 through 104.
As used herein, the terms “cross-linking”, “oxidative cross-linking”, and “cysteine cross-linking” refer the present process of cross-linking the thiol groups of cysteine residues (i.e. forming intermolecular and intramolecular disulfide bonds) under oxidizing conditions. By definition, the formation of intermolecular disulfide bonds occurs between two or more molecules (i.e. a “plurality”) comprising an effective number cross-linkable cysteine residues. As used herein, a “plurality” of molecules will alternatively be referred to herein as a “population” of molecules. In order to promote intermolecular cross-linking, an effective number cross-linkable cysteine residues are incorporated into the linkers/spacers separating the core motifs. In another embodiment, an effective number of cross-linkable cysteine residues are further incorporated into peptidic linkers/spacers separating the multifunctional solubility tag (MST) portion of the fusion peptide/protein from the portion of the solubility tag comprising the peptide of interest (POI). In one embodiment, at least one cross-linkable cysteine residue is incorporated into one or more linkers/spacers used to separate functional domains within the fusion peptide (i.e., core motif sequences within the MST/IBT and/or a link/spacer separating the MST/IBT from the POI), preferably 1 to 20 cysteine residues, more preferably 1 to 10 cysteine residues, and even more preferably 1 to 3 cysteine residues. In a preferred aspect, the core motif sequences within the inclusion body tags should not include any cross-linkable cysteine residues. The peptide of interest (POI) may include one or more cysteine residues so long as the presence of the residues does not adversely impact the desired functionality of the POI once exposed to oxidizing conditions. In a preferred embodiment, the POI portion of the fusion peptide/protein does not contain any cross-linkable cysteine residues.
As used herein, the term “oxidizing conditions” refers to reaction conditions which favor and promote the formation of disulfide bonds between cysteine residues. Disulfide bond formation can be induced by any number of means well known in the art including, but not limited to contacting the cross-linkable cysteine residues with a gas comprised of oxygen (i.e., diatomic [O2] and/or triatomic oxygen [O3]) and/or the addition of chemical oxidants. The use of gas comprising molecular oxygen is preferred. In a further embodiment, a gas comprising diatomic and/or triatomic oxygen is bubbled and/or sparged through the aqueous reaction solution for a period of time to achieve effective oxidative cross-linking. The oxidative cross-linking step may optionally include the act of mixing and/or stirring of the aqueous reaction mixture for optimal results. Examples of chemical oxidants are well-known in the art and may include, but are not limited to peroxide compounds, hypochlorite, halogens, and permanganate salts; to name a few.
As used herein, the term “reducing conditions” refers to reaction conditions which favor and promote the reduction of disulfide bonds between cysteine residues (i.e., breaks disulfide bond used for cross-linking). Disulfide bonds can be reduced by any number of means well known such as the use of nitrogen purge and/or a chemical reducing agent such as Na2SO3, DTT (dithiothreitol), TCEP (tris(2-carboxyethyl)phosphine), 2-mercaptoethanol, 2-mercaptoethylamine, and mixtures thereof. Generally reducing agents include those that contain thiol groups, those that are phosphines and their derivatives as well as sulfites and thiosulfites.
As used herein, the term “pigment” refers to an insoluble, organic or inorganic colorant.
As used herein, the term “hair” as used herein refers to mammalian hair. In one embodiment, the “hair” is preferably human hair, eyebrows, and eyelashes.
As used herein, the term “skin” as used herein refers to mammalian skin. In one embodiment, the “skin” is preferably human skin, or substitutes for human skin, such as pig skin, VITRO-SKIN® and EPIDERMTM.
As used herein, the term “nails” as used herein refers to mammalian nails, such as fingernails, toenails and other keratinaceous nail materials. In one embodiment, the “nails” are preferably human fingernails or toenails.
As used herein, the term “binding affinity” refers to the strength of the interaction of a peptide with its respective substrate/target material (for example, hair, skin, nails, pigments, polymers, affinity media, etc.) Binding affinity can be defined or measured in terms of the binding peptide's dissociation constant (“KD”), or “MB50.”
As used herein, the term “strong affinity” or “high affinity” will refer to a binding affinity having a KD or MB50 value of less than or equal to about 10−5 M, preferably less than or equal to about 10−6 M, more preferably less than or equal to about 10−7 M, more preferably less than or equal to about 10−8 M, even more preferably less than or equal to about 10−9 M, or most preferably less than or equal to about 10−10 M.
As used herein, “KD” corresponds to the concentration of peptide at which the binding site on the target is half occupied, i.e., when the concentration of target with peptide bound (bound target material) equals the concentration of target with no peptide bound. The smaller the dissociation constant, the more tightly the peptide is bound. For example, a peptide with a nanomolar (nM) dissociation constant binds more tightly than a peptide with a micromolar (μM) dissociation constant. Certain embodiments of the invention will have a KD value of 10−5 or less.
As used herein, “MB50” refers to the concentration of the binding peptide that gives a signal that is 50% of the maximum signal obtained in an ELISA-based binding assay. See, e.g., Example 3 of U.S. Patent Application Publication 2005/022683; hereby incorporated by reference. The MB50 provides an indication of the strength of the binding interaction or affinity of the components of the complex. The lower the value of MB50, the stronger, i.e., “better,” the interaction of the peptide with its corresponding substrate. For example, a peptide with a nanomolar (nM) MB50 binds more tightly than a peptide with a micromolar (μM) MB50. Certain embodiments of the invention will have a MB50 value of 10−5 M or less.
As used herein, the terms “bind”, “binding”, and “coupling” are used interchangeably and is meant to convey an association between a fusion peptide and a surface on a target material though a variety of non-covalent interactions, such as ionic bond-based (electrostatic interaction), hydrogen bond-based, hydrophobic bond-based, chelation based, biological specific affinity, a general aggregation or the formation of tertiary or quaternary structures or a combination thereof, but does not include, by proviso, covalent binding.
As used herein, the term “affinity peptide” or “target surface-binding peptide” refers to a peptide having strong affinity for a particular target material or compound. Examples may include, but are not limited to, body surface-binding peptides, pigment-binding peptides, polymer-binding peptides, various mineral-binding peptides, clay-binding peptides, cotton-binding peptides, cellulose-binding peptides, and metal-binding peptides.
As used herein, a “body surface-binding peptide” is an affinity peptide that binds with high affinity to a specified body surface. Examples may include, but are not limited to, hair-binding peptides, skin-binding peptides, nail-binding peptides, and tooth-binding peptides.
As used herein, a “hair-binding peptide” is an affinity peptide that binds with high affinity to hair.
As used herein, a “skin-binding peptide” is an affinity peptide that binds with high affinity to skin.
As used herein, a “nail-binding peptide” is an affinity peptide that binds with high affinity to fingernail or toenail.
As used herein, a “tooth-binding peptide” is an affinity peptide that binds with high affinity to tooth enamel and/or tooth pellicle. In a preferred embodiment, the tooth-binding peptide binds with high affinity to tooth enamel.
As used herein, an “antimicrobial peptide” is a peptide having the ability to kill microbial cell populations (U.S. Pat. No. 7,427,656; hereby incorporated by reference). The amino acid sequences of exemplary antimicrobial peptides are provided as SEQ ID NOs: 393-421.
As used herein, “cellulose-binding peptide” refers to an affinity peptide that binds with high affinity to cellulose. Exemplary cellulose-binding peptides are provided as SEQ ID NOs: 447-452.
As used herein, “clay-binding peptide” refers to a peptide that binds with high affinity to clay. Exemplary clay-binding peptides are provided as SEQ ID NOs: 480-495.
As used herein, “pigment-binding peptide” refers to an affinity peptide that binds with high affinity to a pigment, Examples of pigment-binding peptides are provided as SEQ ID NOs: 422-446.
As used herein, “polymer-binding peptide” refers to an affinity peptide that binds with high affinity to at least one specified polymer. Examples of polymer-binding peptides are provided herein as SEQ ID NOs: 453-479.
As used herein, “metal-binding peptide” refers to an affinity peptide that binds with high affinity to at least one metal. Examples of metal-binding peptides may include, but are not limited to, gold-binding peptides and silver-binding peptides.
As used herein, the term “operably linked” refers to the association of nucleic acid sequences on a single nucleic acid fragment so that the function of one is affected by the other. For example, a promoter is operably linked with a coding sequence when it is capable of affecting the expression of that coding sequence (i.e., that the coding sequence is under the transcriptional control of the promoter). In a further embodiment, the definition of “operably linked” may also be extended to describe the products of chimeric genes, such as fusion peptides. As such, “operably linked” will also refer to the linking of a “leave on” multi-functional solubility tag to a peptide of interest (POI) to be produced, recovered and used as such or for an aqueous composition or formulation.
As used herein, the term “solubility” refers to the amount of a substance that can be dissolved in a unit volume of a liquid under specified conditions. In the present application, the term “solubility” is used to describe the ability of a peptide/fusion peptide to be resuspended in a volume of solubilization medium, e.g. (an aqueous medium such as a buffer medium) used in biochemical applications and may include Tris, saline, MES, and the like. In one embodiment, a peptide may be defined as soluble in a defined medium when it remains in solution after centrifuging the peptide-containing solution for 5 minutes at 15000 rpm (rcf=21130 g) in a standard tabletop microcentrifuge. The POI, when not coupled to the multi-functional inclusion body tag, is soluble within the host cell and/or cell lysate under normal physiological conditions. As used herein, the term “normal physiological conditions within the host cell” may be defined as an aqueous matrix having a pH of about 6.5 to about 8.0 (typical for neutrophiles) at a temperature suitable for growth of the recombinant host cell. One of ordinary skill in the art can easily determine the physiological conditions within the particular host cell used for recombinant production of the present peptides. Fusion of multi-functional inclusion body tag (IBT) to the POI results in the formation of a fusion peptide that is insoluble under normal physiological conditions within the recombinant host cell, resulting in the formation of at least one inclusion body.
The term “amino acid” refers to the basic chemical structural unit of a protein or polypeptide. The following abbreviations are used herein to identify specific amino acids:













Three-Letter
One-Letter


Amino Acid
Abbreviation
Abbreviation







Alanine
Ala
A


Arginine
Arg
R


Asparagine
Asn
N


Aspartic acid
Asp
D


Cysteine
Cys
C


Glutamine
Gln
Q


Glutamic acid
Glu
E


Glycine
Gly
G


Histidine
His
H


Isoleucine
Ile
I


Leucine
Leu
L


Lysine
Lys
K


Methionine
Met
M


Phenylalanine
Phe
F


Proline
Pro
P


Serine
Ser
S


Threonine
Thr
T


Tryptophan
Trp
W


Tyrosine
Tyr
Y


Valine
Val
V


Any naturally-occurring amino acid
Xaa
X


(or as defined by the formulas


described herein)









As used herein, the term “genetic construct” refers to a series of contiguous nucleic acids useful for modulating the genotype or phenotype of an organism. Examples of genetic constructs include but are not limited to a nucleic acid molecule, and open reading frame, a gene, a plasmid and the like.
As used herein, the terms “host cell” and “recombinant host cell” refer to a microbial cell comprising an expressible heterologous nucleic acid molecule encoding a fusion peptide having at least one of the present multi-functional inclusion body tags.
Expressible Peptides of Interest
The peptide of interest (“POI”) targeted for production using the present method is one that is appreciably soluble in the recombinant host cell and/or host cell liquid lysate under normal physiological conditions. In one aspect, the peptides of interest are generally short (<300 amino acids in length) and difficult to recombinantly produce in sufficient amounts due to their solubility and/or exposure to endogenous proteolytic degradation. Fusion of the POI to at least one multi-functional inclusion body tag creates a fusion peptide that is insoluble in the host cell and/or host cell lysate under normal physiological conditions (i.e., inclusion body formation comprising the fusion peptide is observed within the grown host cell). Production of the fusion peptide is typically increased when expressed and accumulated in the form of an insoluble inclusion body as the peptide is generally more protected from endogenous proteolytic degradation. Furthermore, the insoluble fusion peptide can be easily separated from the host cell lysate using a simple separation technique such as centrifugation or filtration. The fusion peptide is not cleaved to remove multi-functional solubility tag that not only facilitates inclusion body formation but also provides surface interactions in downstream applications for forming adducts between two or more surfaces.
In general, the present multi-functional inclusion body tags can be used in a process to produce any peptide of interest that is (1) typically soluble in the cell and/or cell lysate under typical physiological conditions and/or (2) those that can be produced at significantly higher levels when expressed in the form of LOT. In one embodiment, the POI is appreciably soluble in the host cell and/or corresponding cell lysate under normal physiological and/or process conditions.
The length of the POI may vary as long as (1) the POI is appreciably soluble in the host cell and/or cell lysate, and/or (2) the amount of the POI produced is increased when expressed in the form of an insoluble fusion peptide/inclusion body.
The function of the POI is not limited by the present methods and may include, but is not limited to bioactive molecules such as curative agents for diseases (e.g., insulin, interferon, interleukins, peptide hormones, anti-angiogenic peptides, peptide toxins, and peptides (with the proviso that the peptide is not an antibody or an Fab portion of an antibody) that bind to and affect defined cellular targets such as receptors, channels, lipids, cytosolic proteins, and membrane proteins; see U.S. Pat. No. 6,696,089), peptides having an affinity for a particular material such as hair, skin, nail or tooth (see WIPO International Patent Application Publication Nos. WO01/079479, WO04/048399, and WO04/000257; U.S. Patent Application Publication Nos. 2005-0226839, 2010-0247457, and 2010-0247589; U.S. Pat. Nos. 7,736,633; 7,427,656; 7,309,482; 7,749,957; and 7,807,141), cellulose, iron oxides (U.S. Patent Application Publication No. 2010-0158837), silica (U.S. Patent Application Publication No. 2010-0158822), various polymers (U.S. Pat. Nos. 7,709,601; 7,700,716; 7,906,617; and 7,632,919; and U.S. Patent Application Publication No. 2007-0264720), calcium carbonate (U.S. Pat. No. 7,754,680), and clay binding peptides (U.S. Pat. No. 7,749,957), for targeted delivery of at least one benefit agent.
Examples of various affinity peptides and/or anti-microbial peptides are provided herein as amino acid sequence: SEQ ID NOs: 105-392 are exemplary body surface-binding peptides, SEQ ID NOs: 393-421 are exemplary antimicrobial peptides, SEQ ID NOs: 422-446 are exemplary pigment-binding peptides, SEQ ID NOs: 447-452 are exemplary cellulose-binding peptides, SEQ ID NOs: 453-479 are exemplary polymer-binding peptides, and SEQ ID NOs: 480-495 are exemplary clay binding peptides.
Manipulations of Physio-Chemical Conditions to Control Solubility of Fusion Peptides
The solubility of the fusion peptides may vary from peptide to peptide. Anyone skilled in the practice of protein chemistry can determine conditions necessary to control solubility by carrying out systematic titrations of independent parameters (pH, salt, ionic strength, fusion peptide concentration, etc.) or by a sampling of conditions involving multiple parameters using a statistical design of experiments (Atkinson, A. C. and Donev, A. N. and Tobias, R. D. (2007) Optimum Experimental Designs, With SAS. Oxford University Press, New York, N.Y.). Assays to characterize the physical state of the peptide can include observation for turbidity by eye or with a spectrophotometer at a chosen UV or visible wavelength, sedimentation behavior following centrifugation at a chosen centrifugal force followed by the detection of the peptide in the supernatant or the pellet with a dye assay or polyacrylamide gel electrophoresis, or by dynamic light scattering measurement with an instrument like the Malvern Zetasizer (Malvern Instruments Ltd, England). In all experiments, additional parameters should be taken into consideration such as the speed of the change of state and the effect of the initial peptide concentration.
Fusion Peptides
The multifunctional inclusion body tags are used to create chimeric polypeptides (“fusion peptides”) that are insoluble when expressed under the physiological conditions within the host cell, forming inclusion bodies. One of skill in the art will recognize that the elements of the fusion protein can be structured in a variety of ways. The fusion protein will include at least one portion comprising a multifunctional solubility tag (MST) and at least one portion comprising a peptide of interest (POI). The fusion peptide includes one or more peptide spacers separating the core motif sequences within the MST and may include a peptide linker separating the MST from the POI. At least one spacer within the fusion peptide/proteins will include one or more cross-linkable cysteine residues. The MST may be positioned as a leader sequence or a terminator sequence relative to the position of the peptide of interest within the fusion peptide. In another embodiment, a plurality of MSTs and POIs are used when engineering the fusion peptide.
The fusion peptide will typically be insoluble in an aqueous environment at a temperature of 0° C. to 50° C. using a pH range from pH 5 to pH 10, preferably 6 to 10, and most preferably 6 to 8. The temperature, pH, and/or ionic strength of the aqueous environment may be adjusted to obtain the desired solubility characteristics of the fusion peptide/inclusion body.
Multifunctional Solubility Tags Comprising Cross-Linkable Cysteine Residues in the Peptidic Spacers Separating Core Motifs
The present method uses oxidative cross-linking to enhance the binding durability of a fusion peptide bound to a target material surface. The multifunctional solubility tag is engineered to comprise an effective number of cross-linkable cysteine residues within the spacer elements separating the core motifs within the tag.
One of skill in the art can recombinantly engineer an effective number of cross-linkable cysteine residues into the spacer elements of the fusion protein targeted for oxidative cross-linking. In one embodiment, the effective number of cysteine residues is at least 1 within a multifunctional solubility tag (for example, cross-linking between different multifunctional solubility tags within a population of fusion proteins having one or more multifunctional solubility tags), preferably at least 2, more preferably at least 3, and even more preferably at least 4. In another embodiment, the effective number of cysteine residues is 3 to about 20, preferably 3 to about 10, more preferably 3 to about 6, more preferably 3 to about 5, and most preferably 4 to 5 cross-linkable cysteine residues.
The present multi-functional solubility tags have the general formula:

SEQ ID NO: 1—Spacer−[[SEQ ID NO: 1]−[Spacer]m]n or  a)

SEQ ID NO: 2—Spacer−[[SEQ ID NO: 2]−[Spacer]m]n;  b)

wherein

SEQ ID NO: 1 is Xaa1-Gln-[Xaa2]p-[Phe-Xaa3-Xaa4-Xaa5]s-Phe-Xaa6-[Xaa7]q-[Gln]r; and

SEQ ID NO: 2 is Xaa1-Gln-Xaa8-[Xaa4-Xaa8]s-Phe-[Glu-Gln-Gln]r;

wherein

    
    
        Xaa1=Gln or His;
        Xaa2=Gln, Arg, His, or Lys;
        Xaa3=Gln, His, Lys, Arg, or Glu;
        Xaa4=Trp or Phe;
        Xaa5=Gln, His, Lys, Arg or Glu;
        Xaa6=Glu, Gln, or Arg;
        Xaa7=Gln or Lys;
        Xaa8=Asp, Glu, Gln, His, Lys, or Arg;
        p, q, and r are independently 0 or 1;
        s is an integer ranging from 1 to 5;
        n is an integer ranging from 1 to 10;
        m=n or n−1; and
        Spacer=a peptide linker ranging from 1 to 100 amino acids in length, wherein said spacer comprises at least one cross-linkable cysteine residue.
    
    


In one embodiment, multifunctional solubility tags are provided comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 75, 77, 499, 500, 501, 502, 503, 504, and 505.
In another embodiment, multifunctional solubility tags are provided comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 499, 500, 501, 502, 503, 504, and 505.
In another embodiment, multifunctional solubility tags are provided comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 75 and 77.
In certain embodiments, the present multifunctional solubility tags defined by the above general formula may specifically exclude, by proviso, those comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 75 and 77.
In yet a further embodiment, the multifunctional solubility tags may include the polypeptides of SEQ ID NOs: 4, 14-74, and 76 so long as one or more of the spacer elements separating the core motifs in each is modified to comprise an effective number of cross-linkable cysteine residues.
Method to Use Oxidative Cross-linking to Increase the Binding Durability of Fusion Peptides Bound to a Target Material
The present fusion peptide may be designed to have affinity for a target material. The fusion peptide may be bound to the target material (for example, a particle or affinity media) under reducing conditions. Once the fusion peptide-target material complex is formed, the complex is subsequently exposed to oxidizing conditions whereby the cross-linkable cysteines form disulfide bonds. The binding durability of the cross-linked fusion peptides/proteins bound to the target material is increase due to the cross-linking. The fusion peptide may have enhanced binding durability for the target material in the presence of various conditions including, but not limited to, changes in pH, changes in temperature, changes in ionic strength, the presence of absence of a certain compound, the presence of one or more surfactants, such as sodium lauryl ether sulfate (SLES), and combinations thereof. Methods to assess the changes in binding durability of the cross-linked verse non-cross-linked fusion peptide complexes are described herein and can be practiced by one of ordinary skill in the art.
In one embodiment, a method is provided comprising:

    
    
        a) providing an aqueous solution comprising a population of fusion peptides, said fusion peptides having the general structure:
        MST-POI or
        POI-MST;
        wherein
        MST is a multi-functional solubility tag; and
        POI is a peptide of interest operably linked to the MST;
        wherein the multi-functional solubility tag (MST) has the general formula of:

SEQ ID NO: 1—Spacer−[[SEQ ID NO: 1]−[Spacer]m]n  (i)

or

SEQ ID NO: 2—Spacer−[[SEQ ID NO: 2]−[Spacer]m]n;  (ii)

wherein

SEQ ID NO: 1 is Xaa1-Gln-[Xaa2]p-[Phe-Xaa3-Xaa4-Xaa5]s-Phe-Xaa6-[Xaa7]q-[Gln]r; and

SEQ ID NO: 2 is Xaa1-Gln-Xaa8-[Xaa4-Xaa8]s-Phe-[Glu-Gln-Gln]r;

        wherein
        Xaa1=Gln or His;
        Xaa2=Gln, Arg, His, or Lys;
        Xaa3=Gln, His, Lys, Arg, or Glu;
        Xaa4=Trp or Phe;
        Xaa5=Gln, His, Lys, Arg or Glu;
        Xaa6=Glu, Gln, or Arg;
        Xaa7=Gln or Lys;
        Xaa8=Asp, Glu, Gln, His, Lys, or Arg;
        p, q, and r are independently 0 or 1;
        s is an integer ranging from 1 to 5;
        n is an integer ranging from 2 to 10;
        m=n or n−1; and
        Spacer=a peptide linker ranging from 1 to 100 amino acids in length; wherein said spacer comprises at least one cross-linkable cysteine residue; wherein the aqueous solution has a pH of at least 10 and wherein the at least one cross-linkable cysteine residue is reduced;
        b) contacting the aqueous solution of (a) with a first target material whereby a mixture if formed;
        c) altering the pH of the mixture of (b) whereby at least a portion of the population of fusion peptides non-covalently associate with the first target material, forming one or more fusion peptide-first target material complexes; wherein the association between the fusion peptides and the first target material is dependent upon, or enhanced by, the presence of the multi-functional solubility tag;
        d) subjecting the fusion peptide-first target material complexes of (c) to oxidizing conditions whereby cysteine residues cross-link; and
        e) optionally recovering the product of step (d).
    
    


The method may also include an initial step of recombinantly producing the fusion peptide in a microbial host cell. As such, a method is also provided comprising:

    
    
        a) providing a host cell comprising an expressible genetic construct encoding an insoluble fusion peptide comprising at least one first portion and at least one second portion, wherein said first portion comprises a multi-functional solubility tag (MST) and said second portion comprises a peptide of interest (POI); wherein the multi-functional solubility tag (MST) has the general formula of:

SEQ ID NO: 1—Spacer−[[SEQ ID NO: 1]−[Spacer]m]n or  (i)

SEQ ID NO: 2—Spacer−[[SEQ ID NO: 2]−[Spacer]m]n;  (ii)

        wherein

SEQ ID NO: 1 is Xaa1-Gln-[Xaa2]p-[Phe-Xaa3-Xaa4-Xaa5]s-Phe-Xaa6-[Xaa7]q-[Gln]r; and

SEQ ID NO: 2 is Xaa1-Gln-Xaa8-[Xaa4-Xaa8]s-Phe-[Glu-Gln-Gln]r;

        wherein
        Xaa1=Gln or His;
        Xaa2=Gln, Arg, His, or Lys;
        Xaa3=Gln, His, Lys, Arg, or Glu;
        Xaa4=Trp or Phe;
        Xaa5=Gln, His, Lys, Arg or Glu;
        Xaa6=Glu, Gln, or Arg;
        Xaa7=Gln or Lys;
        Xaa8=Asp, Glu, Gln, His, Lys, or Arg;
        p, q, and r are independently 0 or 1;
        s is an integer ranging from 1 to 5;
        n is an integer ranging from 2 to 10;
        m=n or n−1; and
        Spacer=a peptide linker ranging from 1 to 100 amino acids in length; wherein said spacer comprises at least one cross-linkable cysteine residue;
        b) growing the microbial host cell under conditions whereby the insoluble fusion peptide is produced within the host cell in the form of at least one inclusion body;
        c) recovering the insoluble fusion peptide from the microbial host cell;
        d) subjecting the recovered insoluble fusion peptide of (c) to aqueous reducing conditions have a pH of at least 10 for a period of time sufficient to solubilize the insoluble fusion peptide and reduce cross-linkable cysteine residues; whereby an aqueous solution comprising a population of reduced fusion peptides is produced;
        e) contacting the aqueous solution comprising the population of reduced fusion peptides of (d) with a first target material whereby a mixture is formed;
        f) altering the pH of the mixture of (e) whereby at least a portion of the population of reduced fusion peptides non-covalently associates with the first target material forming fusion peptide-first target material complexes; wherein the association between the fusion peptides and the first target material is dependent upon, or enhanced by, the presence of the multi-functional solubility tag;
        g) subjecting the fusion peptide-first target material complexes of (f) to oxidizing conditions whereby the cysteine residues cross-link; and
        h) optionally recovering the product of step (g).
    
    


In one embodiment, the fusion proteins are 30 to 600 amino acids in length.
In another embodiment, the multifunctional inclusion body tags are less than 400 amino acids in length.
In another embodiment, reducing conditions comprises a pH of least 11 or a pH of least 12. In another embodiment, the reducing conditions comprises at least one reducing agent. In a preferred embodiment, the reducing agent is selected from the group consisting of β-mercaptoethanol, dithioerythritol, thioglycolate, NaBH4, cysteine, a thiol compound, dithionite, bisulfite, H2S, Na2S, Tris(2-carboxyethyl)phosphine hydrochloride, and mixtures thereof.
In another embodiment, the oxidizing conditions comprises the presence of a gas comprising an effective amount of diatomic or triatomic oxygen or peroxide such as hydrogen peroxide.
In another embodiment, the fusion peptide is produced inside a microbial expression host in a reduced state.
In another embodiment, the step of altering of the pH of the aqueous mixture is reducing the pH. In a preferred aspect, the pH is reduced to 8 or less. In yet another aspect, the pH is reduced using dialysis. In a further embodiment, dialysis is used when subjecting the fusion peptide-first target material complex to oxidizing conditions.
In one embodiment of the present method, the POI of the fusion peptide is characterized by a binding functionality, an antimicrobial functionality an enzymatic activity, hydrophobicity, enzyme recognition sequence or any combination thereof.
In another embodiment, the POI of the fusion peptide is characterized by a binding functionality; wherein the binding functionality is a strong affinity for a second target material; wherein the first target material and the second target material are different.
In another embodiment, the first target material is a particle having an average particle size ranging from 3 nm to 10 μm as measured by a light scattering method.
In another embodiment, the second target material is selected from the group consisting of a pigment, a body tissue, a cell surface receptor, hair, skin, nail, teeth, oral cavity tissues, plant tissue, a polymer, polystyrene, polyethylene, polypropylene, polytetrafluoroethylene, polyester, polyvinyl chloride, poly(methyl methacrylate), polyethersulfone, polyimide, polyamide, aramids, poly para-phenylene terephthalamide, poly meta-phenylene terephthalamide, poly urethanes, protein fibrils, polysaccharides, cellulose, starch, chitin, minerals, silica, silicates, micas, titanium dioxide, tungsten carbide, alumina, iron oxides, clays, metals, gold, silver, carbon, carbon black, graphite and carbon nanotubes.
In a further embodiment, the second target material is a keratin-containing material selected from the group consisting of skin, nail, and hair.
In another embodiment, the first target material is selected from the group consisting of a pigment, a body tissue, a cell surface receptor, hair, skin, nail, teeth, oral cavity tissues, plant tissue, a polymer, polystyrene, polyethylene, polypropylene, polytetrafluoroethylene, polyester, polyvinyl chloride, poly(methyl methacrylate), polyethersulfone, polyimide, polyamide, aramids, poly para-phenylene terephthalamide, poly meta-phenylene terephthalamide, poly urethanes, protein fibrils, polysaccharides, cellulose, starch, chitin, minerals, silica, silicates, micas, titanium dioxide, alumina, iron oxides, clays, metals, gold, silver, carbon, carbon black, graphite and carbon nanotubes.
In another embodiment, the first portion of the fusion peptide is capable of forming a hydrogel and the second portion has affinity for a human tissue or cell surface receptor.
In another embodiment, the second portion having affinity for a human tissue or cell surface receptor comprises at least one arginine-glycine-aspartic acid (RGD) peptide.
Examples of Applications Incorporating Fusion Peptide Comprising Cross-Linkable Cysteine Residues in the Multifunctional Solubility Tags
Multifunctional solubility tags comprising cross-linkable cysteine residues, fusion peptides comprising such multifunctional solubility tags and at least one peptide of interest (POI), and fusion peptide-target material complexes may be used in a variable of applications. Examples of end use applications may include, but are not limited to, personal care products, cosmetic products, affinity media (comprising a bound fusion peptide coupled to a solid support such as a resin, a membrane, a filter, a bead, a particle, a fiber, a foam, a film or any combination thereof), pharmaceutical products, agricultural products, biomedical products, and tissue engineering products, to name a few.
In one embodiment, a composition comprising a particle comprising one of the present fusion peptides is provided. The particle may be partially or completely coated with the present cross-linked fusion proteins. In a preferred embodiment, the particle comprises an average particle size of 3 nm to 10 μm as measured by a light scattering method.
In another embodiment, a personal care product is provided comprising one (or more) of the present fusion peptides or a particle composition comprising one or more of the present fusion peptides and a In one embodiment, the personal care product is selected from the group consisting of shampoos, hair gels, hair sprays, mousses, hair coloring products, hair bleaching products, hair conditioners, body washes, skin creams, lotions, skin moisturizers, sunscreens, tonics, toothpastes, dental creams, tooth gels, tooth powders, mouth washes, breath fresheners, and dental floss.
An affinity media is also provided comprising a solid support and an effective amount of at least one of the present fusion peptides (oxidatively cross-linked using the incorporated cysteine residues). In one embodiment, an affinity media is provided comprising an effective amount of a fusion peptide coating, said fusion peptide having a first portion and a second portion, wherein said first portion comprises a multi-functional solubility tag (MST) that is bound to the solid support and said second portion of the fusion peptide has an affinity for a target material; wherein the multi-functional solubility tag has the general formula:

SEQ ID NO: 1—Spacer−[[SEQ ID NO: 1]−[Spacer]m]n or  a)

SEQ ID NO: 2—Spacer−[[SEQ ID NO: 2]−[Spacer]m]n;  b)

wherein

SEQ ID NO: 1 is Xaa1-Gln-[Xaa2]p-[Phe-Xaa3-Xaa4-Xaa5]s-Phe-Xaa6-[Xaa7]q-[Gln]r; and

SEQ ID NO: 2 is Xaa1-Gln-Xaa8-[Xaa4-Xaa8]s-Phe-[Glu-Gln-Gln]r;

wherein

    
    
        Xaa1=Gln or His;
        Xaa2=Gln, Arg, His, or Lys;
        Xaa3=Gln, His, Lys, Arg, or Glu;
        Xaa4=Trp or Phe;
        Xaa5=Gln, His, Lys, Arg or Glu;
        Xaa6=Glu, Gln, or Arg;
        Xaa7=Gln or Lys;
        Xaa8=Asp, Glu, Gln, His, Lys, or Arg;
        p, q, and r are independently 0 or 1;
        s is an integer ranging from 1 to 5;
        n is an integer ranging from 1 to 10;
        m=n or n−1; and
        Spacer=a peptide linker ranging from 1 to 100 amino acids in length, wherein said spacer comprises at least one cross-linkable cysteine residue.
    
    


In another embodiment, the affinity media solid support comprises a material selected from the group consisting of a pigment, a plant tissue, a polymer, polystyrene, polyethylene, polypropylene, polytetrafluoroethylene, polyester, polyvinyl chloride, poly(methyl methacrylate), polyethersulfone, polyimide, polyamide, aramids, poly para-phenylene terephthalamide, poly meta-phenylene terephthalamide, poly urethane, polysaccharides, cellulose, starch, chitin, minerals, silica, silicates, micas, titanium dioxide, alumina, iron oxides, clays, metals, gold, silver, carbon, carbon black, graphite and carbon nanotubes.
The affinity media solid support may in a form such as a resin, a membrane, a filter, a bead, a particle, a fiber, a foam, a film or any combination thereof.
In a further embodiment, the affinity media as described above is provided wherein the second portion of the fusion peptide has affinity for a second target a material that may be present in a biological fluid, an aqueous waste stream, a waste stream from mining operations, an environmental sample, a fermentation medium, fermentation biomass.
In another embodiment, a pharmaceutical, agricultural, or cosmetic composition comprising at least one of the present fusion peptide is also provided. In one embodiment, the pharmaceutical composition comprises at least one of the present fusion peptides and one or more pharmaceutically acceptable ingredients. As used herein, “pharmaceutically acceptable” means that drugs, medicaments and/or inert ingredients which the term describes are suitable for use in contact with the tissues of humans and other animals without undue toxicity, incompatibility, instability, irritation, allergic response, and the like, commensurate with a reasonable benefit/risk ratio.
In another embodiment, a biomedical or tissue engineering composition comprising at least one of the present fusion peptides is also provided. In one aspect, the biomedical or tissue engineering composition comprises a fusion peptide comprises a multifunctional solubility tag having hydrogel forming activity and a second portion having affinity for a cell surface receptor.
The RGD peptide motif (arginine-glycine-aspartic acid) can be found in proteins of the extracellular matrix. Integrins link the intracellular cytoskeleton of cells with the extracellular matrix by recognizing this RGD motif. RGD peptides have been show to induce apoptosis and might be used as drugs against angiogenesis, inflammation and cancer metastasis. In a further embodiment, the biomedical or tissue engineering composition describe above comprises a fusion peptide wherein the second portion having affinity for the cell surface receptor comprising at least one arginine-glycine-aspartic acid (RGD) peptide motif.
Method to Make a Peptide of Interest Using Insoluble Fusion Peptides
A genetic construct is prepared encoding a fusion peptide comprising at least one “leave-on” multifunctional inclusion body tag and at least one peptide of interest, wherein the tag(s) and the POI(s) may be separated by peptide spacers/linkers. Expression of the genetic construct encoding the fusion protein produces an insoluble form of the peptide of interest that accumulates in the form of inclusion bodies within the host cell. The host cell is grown for a period of time sufficient for the insoluble fusion peptide to accumulate within the cell.
The host cell is subsequently lysed using any number of techniques well known in the art. The insoluble fusion peptide/inclusion bodies are then separated from the soluble components of the cell lysate using a simple and economical technique, such as centrifugation and/or filtration.
Transformation and Expression
Construction of genetic cassettes and vectors that may be transformed into an appropriate expression host is common and well known in the art. Typically, the vector or cassette contains sequences directing transcription and translation of the relevant chimeric construct, a selectable marker, and sequences allowing autonomous replication or chromosomal integration. Suitable vectors comprise a region 5′ of the gene which harbors transcriptional initiation controls and a region 3′ of the DNA fragment which controls transcriptional termination. It is most preferred when both control regions are derived from genes homologous to the transformed host cell, although it is to be understood that such control regions need not be derived from the genes native to the specific species chosen as a production host.
Transcription initiation control regions or promoters, which are useful to drive expression of the genetic constructs encoding the fusion peptides in the desired host cell are numerous and familiar to those skilled in the art. Virtually any promoter capable of driving these constructs is suitable for the present invention including, but not limited to CYC1, HIS3, GAL1, GAL10, ADH1, PGK, PHO5, GAPDH, ADC1, TRP1, URA3, LEU2, ENO, TPI (useful for expression in Saccharomyces); AOX1 (useful for expression in Pichia); and lac, ara (pBAD), tet, trp, IPL, IPR, T7, tac, and trc (useful for expression in Escherichia coli) as well as the amy, apr, npr promoters and various phage promoters useful for expression in Bacillus. 
Termination control regions may also be derived from various genes native to the preferred hosts. Optionally, a termination site may be unnecessary; however, it is most preferred if included.
Preferred host cells for expression of the fusion peptides are microbial hosts that can be found broadly within the fungal or bacterial families and which grow over a wide range of temperature, pH values, and solvent tolerances. Because the transcription, translation, and the protein biosynthetic apparatus is the same irrespective of the cellular feedstock, genes are expressed irrespective of the carbon feedstock used to generate the cellular biomass. Large-scale microbial growth and functional gene expression may utilize a wide range of simple or complex carbohydrates, organic acids and alcohols, saturated hydrocarbons such as methane or carbon dioxide in the case of photosynthetic or chemoautotrophic hosts. The functional genes may be regulated, repressed or depressed by specific growth conditions, which may include the form and amount of nitrogen, phosphorous, sulfur, oxygen, carbon or any trace micronutrient including small inorganic ions. In addition, the regulation of functional genes may be achieved by the presence or absence of specific regulatory molecules that are added to the culture and are not typically considered nutrient or energy sources. Growth rate may also be an important regulatory factor in gene expression. Examples of host strains include, but are not limited to fungal or yeast species such as Aspergillus, Trichoderma, Saccharomyces, Pichia, Yarrowia, Candida, Hansenula, or bacterial species such as Salmonella, Bacillus, Acinetobacter, Zymomonas, Agrobacterium, Erythrobacter, Chlorobium, Chromatium, Flavobacterium, Cytophaga, Rhodobacter, Rhodococcus, Streptomyces, Brevibacterium, Corynebacteria, Mycobacterium, Deinococcus, Escherichia, Erwinia, Pantoea, Pseudomonas, Sphingomonas, Methylomonas, Methylobacter, Methylococcus, Methylosinus, Methylomicrobium, Methylocystis, Alcaligenes, Synechocystis, Synechococcus, Anabaena, Thiobacillus, Methanobacterium, Klebsiella, and Myxococcus. 
Preferred bacterial host strains include Escherichia, Pseudomonas, and Bacillus. In a highly preferred aspect, the bacterial host strain is Escherichia coli. 
Fermentation Media
Fermentation media in the present invention must contain suitable carbon substrates. Suitable substrates may include, but are not limited to, monosaccharides such as glucose and fructose, disaccharides such as lactose or sucrose, polysaccharides such as starch or cellulose or mixtures thereof and unpurified mixtures from renewable feedstocks such as cheese whey permeate, cornsteep liquor, sugar beet molasses, and barley malt. It is contemplated that the source of carbon utilized may encompass a wide variety of carbon containing substrates and will only be limited by the choice of organism. Although it is contemplated that all of the above mentioned carbon substrates and mixtures thereof are suitable in the present invention, preferred carbon substrates are glucose, fructose, and sucrose.
In addition to an appropriate carbon source, fermentation media must contain suitable minerals, salts, cofactors, buffers and other components, known to those skilled in the art, suitable for the growth of the cultures and promotion of the expression of the fusion peptides.
Culture Conditions
Suitable culture conditions can be selected dependent upon the chosen production host. Typically, cells are grown at a temperature in the range of about 25° C. to about 40° C. in an appropriate medium. Suitable growth media may include common, commercially-prepared media such as Luria Bertani (LB) broth, Sabouraud Dextrose (SD) broth or Yeast medium (YM) broth. Other defined or synthetic growth media may also be used and the appropriate medium for growth of the particular microorganism will be known by one skilled in the art of microbiology or fermentation science. The use of agents known to modulate catabolite repression directly or indirectly, e.g., cyclic adenosine 2′:3′-monophosphate, may also be incorporated into the fermentation medium. Suitable pH ranges for the fermentation are typically between pH 5.0 to pH 9.0, where pH 6.0 to pH 8.0 is preferred. Fermentations may be performed under aerobic or anaerobic conditions where aerobic conditions are generally preferred.
Industrial Batch and Continuous Fermentations
A classical batch fermentation is a closed system where the composition of the medium is set at the beginning of the fermentation and not subject to artificial alterations during the fermentation. Thus, at the beginning of the fermentation the medium is inoculated with the desired organism or organisms, and fermentation is permitted to occur without adding anything to the system. Typically, a “batch” fermentation is batch with respect to the addition of carbon source and attempts are often made at controlling factors such as pH and oxygen concentration. In batch systems the metabolite and biomass compositions of the system change constantly up to the time the fermentation is stopped. Within batch cultures cells moderate through a static lag phase to a high growth log phase and finally to a stationary phase where growth rate is diminished or halted. If untreated, cells in the stationary phase will eventually die. Cells in log phase generally are responsible for the bulk of production of end product or intermediate.
A variation on the standard batch system is the Fed-Batch system. Fed-Batch fermentation processes are also suitable in the present invention and comprise a typical batch system with the exception that the substrate is added in increments as the fermentation progresses. Fed-Batch systems are useful when catabolite repression is apt to inhibit the metabolism of the cells and where it is desirable to have limited amounts of substrate in the media. Measurement of the actual substrate concentration in Fed-Batch systems is difficult and is therefore estimated on the basis of the changes of measurable factors such as pH, dissolved oxygen and the partial pressure of waste gases such as CO2. Batch and Fed-Batch fermentations are common and well known in the art and examples may be found in Thomas D. Brock in Biotechnology: A Textbook of Industrial Microbiology, Second Edition (1989) Sinauer Associates, Inc., Sunderland, Mass. (hereinafter “Brock”), or Deshpande, Mukund V., Appl. Biochem. Biotechnol., 36:227 (1992).
Although biomass production may be performed in batch mode, it is contemplated that the production method would be adaptable to continuous fermentation methods. Continuous fermentation is an open system where a defined fermentation medium is added continuously to a bioreactor and an equal amount of conditioned media is removed simultaneously for processing. Continuous fermentation generally maintains the cultures at a constant high density where cells are primarily in log phase growth.
Continuous fermentation allows for the modulation of one factor or any number of factors that affect cell growth or end product concentration. For example, one method will maintain a limiting nutrient such as the carbon source or nitrogen level at a fixed rate and allow all other parameters to moderate. In other systems a number of factors affecting growth can be altered continuously while the cell concentration, measured by media turbidity, is kept constant. Continuous systems strive to maintain steady state growth conditions and thus the cell loss due to the medium being drawn off must be balanced against the cell growth rate in the fermentation.
It is contemplated that the present methods may be practiced using either batch, fed-batch or continuous processes and that any known mode of fermentation would be suitable.
EXAMPLES
The present invention is further defined in the following Examples. It should be understood that these Examples, while indicating preferred embodiments of the invention, are given by way of illustration only. From the above discussion and these Examples, one skilled in the art can ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various uses and conditions.
The meaning of abbreviations used is as follows: “min” means minute(s), “h” means hour(s), “μL” means microliter(s), “mL” means milliliter(s), “L” means liter(s), “nm” means nanometer(s), “mm” means millimeter(s), “cm” means centimeter(s), “μm” means micrometer(s), “mM” means millimolar, “M” means molar, “mmol” means millimole(s), “μmol” means micromole(s), “pmol” means picomole(s), “g” means gram(s), “μg” means microgram(s), “mg” means milligram(s), “g” means the gravitation constant, “rpm” means revolutions per minute, “DTT” means dithiothreitol, and “cat #” means catalog number.
General Methods
Standard recombinant DNA and molecular cloning techniques used herein are well known in the art and are described by Sambrook, J. and Russell, D., Molecular Cloning: A Laboratory Manual, Third Edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (2001); and by Silhavy, T. J., Bennan, M. L. and Enquist, L. W., Experiments with Gene Fusions, Cold Spring Harbor Laboratory Cold Press Spring Harbor, N.Y. (1984); and by Ausubel, F. M. et. al., Short Protocols in Molecular Biology, 5th Ed. Current Protocols and John Wiley and Sons, Inc., N.Y., 2002.
Materials and methods suitable for the maintenance and growth of bacterial cultures are also well known in the art. Techniques suitable for use in the following Examples may be found in Manual of Methods for General Bacteriology, Phillipp Gerhardt, R. G. E. Murray, Ralph N. Costilow, Eugene W. Nester, Willis A. Wood, Noel R. Krieg and G. Briggs Phillips, eds., American Society for Microbiology, Washington, D.C., 1994, or in Brock (supra). All reagents, restriction enzymes and materials used for the growth and maintenance of bacterial cells were obtained from BD Diagnostic Systems (Sparks, Md.), Invitrogen (Carlsbad, Calif.), Life Technologies (Rockville, Md.), QIAGEN (Valencia, Calif.) or Sigma-Aldrich Chemical Company (St. Louis, Mo.), unless otherwise specified.
Example 1
Expression Plasmid Constructs
The purpose of this example is to describe a generic construction of a plasmid encoding for the expression of a LOT peptide.
The region downstream of the promoter in each of the vectors was designed to facilitate and simplify swapping of the DNA constructs encoding multi-functional solubility tags (alone or in combination with the peptide of interest (POI). In general, the nucleic acid molecules were designed to include the appropriate NdeI/BamHI (for region encoding the multi-functional solubility tags) and BamHI/AscI restriction sites (for region encoding POI) to facilitate insertion in the expression vector. More specific description of the construction of the various constructs is given below.
Construction of pLR557, the Expression Plasmid Encoding a Fusion Peptide Comprising the Multi-Functional Solubility Tag IBT187 Coupled to the Peptide of Interest HC263 (IBT187.HC263).
Plasmid pLR557 was derived from the commercially available plasmid pBAD-HisA (Invitrogen). pLR557 harbors the gene for the araC regulator. araC is critical for arabinose promoter function. Additionally the plasmid pLR557 comprises a ColE1 type origin of replication, a bla gene to confer ampicillin resistance and aadA-1 gene to confer spectinomycin (Spec) resistance.
To construct pLR557, a modified multiple cloning site (MCS) was cloned in pBAD-HisA. An NdeI restriction site at position 2844 was eliminated to create a single NdeI site downstream of the pBAD promoter and the resulting plasmid was named pBAD-HisA_MCSmod. The NdeI/EcoRI fragment of plasmid pKSIC4-HC77623 (U.S. Pat. No. 7,285,264) was inserted into the NdeI/EcoRI site of pBAD-HisA_MCSmod, generating plasmid pSF004_pBAD-KSIC4-HC77623. The HindIII fragment of plasmid pCL1920 (Lerner and Inouye, Nucleic Acids Research, 18:4631 (1990); GENBANK® Accession No. AB236930) comprising the spectinomycin resistance gene (aadA-1) was inserted into pSF004_pBAD-KSI4-HC77623, creating plasmid pLR042. Plasmid pLR557 was created from plasmid pLR042 by removing the coding region for the KSIC4-HC77623 fusion peptide and inserting the coding region (SEQ ID NO: 7) for fusion peptide IBT187-HC263 (SEQ ID NO: 8) comprising the multi-functional solubility tag IBT187 linked in tandem to the peptide of interest (POI) HC263.
Construction of pLR642, the Expression Plasmid Encoding a Fusion Peptide Comprising Solubility Tag IBT233 Coupled to the Peptide of Interest HC263 (IBT233.HC263)
pLR642 was derived from plasmid pLR042 by removing the coding region for the KSIC4-HC77623 fusion peptide and inserting the coding region (SEQ ID NO: 12) for fusion peptide IBT233.HC263 (SEQ ID NO: 13). Many additional plasmids encoding variant IBTs were constructed using similar strategy.
Construction of pLR562, the Expression Plasmid for IBT187.H2-TonB-G3
pLR562 was derived from plasmid pLR042 by removing the coding region for the KSIC4-HC77623 fusion peptide and inserting the coding region (SEQ ID NO: 9) for a multi-functional solubility tag 187 linked to the polypeptide H2-TonB-G3 (i.e., IBT187.H2-TonB-G3; SEQ ID NO: 10).
Construction of pLR565, the Expression Plasmid for LOT Comprising IBT (IBT187.1)
The plasmid pLR565 was constructed to drive the expression of the gene IBT187.1 (SEQ ID NO: 3) in E. coli KK2000 for the production of multi-functional peptide tag IBT187.1 (SEQ ID NO: 4). pLR565 was derived from pLR548 by introducing a stop codon after the IBT 187.1 coding sequence. pLR548 is a derivative of the pBAD expression vector (See FIG. 1 for a map of pLR548, SEQ ID NO: 78).
Construction of pLD001-233, the Expression Plasmid for IBT233
The plasmid pLD001-233 was used to drive the expression of a polynucleotide encoding IBT233 (SEQ ID: 11) in E. coli BL21-AI (Invitrogen) for the production of the multi-functional inclusion body tag IBT233 (SEQ ID NO: 37). pLD001-233 is a derivative of the T7 expression vector. (See FIG. 2 for a map of pLD001-233, SEQ ID NO: 79).
Example 2
Accumulation of the Multi-Functional Solubility Tags as Inclusion Bodies
The purpose of this example is to describe the production of a peptide (a multi-functional solubility tag) in a bacterial host by its accumulation as insoluble inclusion bodies.
Strain KK2000 is a derivative of E. coli MG1655 (ATCC 46076TM) strain wherein the endogenous chromosomal copy of the araBAD operon has been deleted. The expression plasmids pLR565, pLR557, pLR642 and pLR562 described in Example 1 were individually transformed into the E. coli strain KK2000. Plasmid pLD001-233, containing a T7 promoter that drives expression of the gene of interest, was transformed into E. coli BL21-AI (Invitrogen). Approximately 30 μL of overnight cultures of individual E. coli transformants (both KK2000 and BL21-AI) were inoculated in 3 mL of LB medium (plus 100 μg/mL of ampicillin). The culture was grown to an OD600 of about 0.4 and the recombinant proteins were produced by the addition of 0.2% arabinose and grown for 3 hours. To determine soluble versus insoluble cell content, the cells were lysed with CelLytic Express (a mixture of non-denaturing detergents and enzymes available from Sigma, St. Louis, USA) and soluble and insoluble fractions were analyzed on an SDS-PAGE gel. The multi-functional solubility tags IBT187.1 and IBT233 were each produced in the form of insoluble inclusion bodies.
In a similar fashion, plasmids pLR557, pLR642, and pLR562 were used to recombinantly produce insoluble fusion peptides IBT187.HC263 (SEQ ID NO: 8), IBT233.HC263 (SEQ ID NO: 13) and IBT187.H2-TonB-G3 (SEQ ID NO: 10), respectively.
Example 3
Production and Purification of Inclusion Bodies Produced from IBT187.1, IBT233, IBT187.HC263, IBT233.HC263, and IBT187.H2-TonB-G3
The purpose of this example is to describe a general process for the production and recovery of the insoluble peptides from the fermentation of the microbial host to the recovery and purification of the inclusion bodies.
The cells containing the two different inclusion body tags and three different fusion peptide constructs were each grown at 37° C. for 20 hr in 1 liter autoinduction media (Na2HPO4, 7.1 g; KH2PO4, 6.8 g; (NH4)2SO4, 3.3 g; MgSO4, 0.36 g; Tryptone, 9.2 g; Yeast Extract, 4.6 g; NaCl, 4.6 g; glycerol, 7.5 g; D-glucose, 0.75 g; and L-arabinose, 0.5 g).
The cells were harvested by centrifugation and lysed in 200 mL lysis buffer (50 mM Tris pH 7.5, 10 mM EDTA, 50 mg lysozyme), followed by sonication on ice for 40 seconds. The suspensions were incubated at 37° C. with shaking for 30 min, followed by being frozen overnight at −20° C. Upon thawing, the inclusion bodies were harvested by centrifugation. The inclusion body pellets were resuspended and washed with 200 mL of wash solution (50 mM Tris pH 7.5, 100 mM NaCl, 2 mM EDTA), and harvested by centrifugation. The inclusion body pellets were washed with 200 mL of water, harvested by centrifugation, and lyophilized.
All the above constructs formed inclusion bodies and remained as pellets under the conditions of harvest and washes.
Example 4
Solubilization of Solubility Tags IBT187.1, IBT233, and Fusion Peptides IBT187.HC263, IBT233.HC263, and IBT187.H2-TonB-G3 at pH 10
The purpose of this example is to describe the solubilization of representative peptides by resuspension of inclusion bodies at alkaline pH.
Constructs comprising multi-functional solubility tags IBT187.1 and IBT233 and fusion peptides IBT187.HC263, IBT233.HC263, and IBT187.H2-TonB-G3 were individually expressed as inclusion bodies in E. coli. This indicates that under normal physiological conditions (around neutral pH and in the presence of salt as found in the cells) these peptides would be in insoluble form as observed in Example 3. The recovered inclusion bodies were tested for solubility in de-ionized water adjusted to pH 10 with sodium hydroxide.
In each case the inclusion bodies were solubilized at 20 μM concentration of the inclusion bodies.
Example 5
Additional Multifuntional Inclusion Body Tags Designed to Have Controllable Solubility
The purpose of this example is to demonstrate that additional peptide solubility tags and/or fusion peptides comprising such multi-functional solubility tags can be prepared from structurally similar peptide tags. The present solubility tags and/or fusion peptides comprising at least one of the solubility tags are processable by controlling their solubility via changing of the physio-chemical conditions of the medium.
Variants of inclusion body tag IBT139 (SEQ ID NO: 14; see U.S. Pat. Nos. 7,678,883 and 7,794,979) were prepared. IBT139 and the variant peptide tags derived from IBT139 were prepared and tested for controllable solubility. Table 1 provides data on the various multi-functional solubility tags.











TABLE 1









SEQ ID


Peptide



NO(s): of


Tag

SEQ ID

Core


Name
Amino Acid Sequence1
NO:
Core Motif(s)
Motif(s)



















IBT139
MQQRFQWQFEQQPRGQQRFQWQFEQQPRGQQRFQWQFEQQPEG
14
QQRFQWQFEQQ
89



QQRFQWQFEQQGSDP





 


IBT187.1
MQQKFKWKFQQQPRGQQKFKWKFQQQPRGQQKFKWKFQQQPEGQ
4
QQKFKWKFQQQ
99



QKFKWKFQKQ

QQKFKWKFQKQ
102


 


IBT201
MASQQRFQWQFQQQPRGQQRFQWQFQQQPEGQQRFQWQFQQQGPGSDP
15
QQRFQWQFQQQ
90


 


IBT202
MASQQRFQWQFQQQPRGQQRFQWQFQQQPRGQQRFQWQFQQQPEGQQRFQWQ
16
QQRFQWQFQQQ
90



FQQQGPGSDP





 


IBT203
MASQQRFQWQFQQQPRGQQRFQWQFQQQPEGQQRFQWQFQQQGPGSGGAGSPG
17
QQRFQWQFQQQ
90



SAGGPGSDP





 


IBT204
MASQQRFQWQFQQQPRGQQRFQWQFQQQPRGQQRFQWQFQQQPEGQQRFQWQ
18
QQRFQWQFQQQ
90



FQQQGPGSGGAGSPGSAGGPGSDP





 


IBT205
MASQQRFQWQFRQQPRGQQQFRWQFQQQPEGQQRFQWQFRQQGPGSGGAGSPG
19
QQRFQWQFRQQ
92



SAGGPGSDP

QQQFRWQFQQQ
86


 


IBT206
MASQQQFRWQFQQQPRGQQRFQWQFRQQPEGQQQFQWRFQQQGPGSGGAGSPG
20
QQQFRWQFQQQ
86



SAGGPGSDP

QQRFQWQFRQQ
92


 


IBT207
MASQQRFRWRFQQQPRGQQRFEWEFQQQPRGQQRFRWRFQQQPEGQQRFEWEF
21
QQRFRWRFQQQ
98



QQQGPGSDP

QQRFEWEFQQQ
100


 


IBT208
MASQQRFRWRFQQQPRGQQRFEWEFQQQPRGQQRFRWRFQQQP
22
QQRFRWRFQQQ
98



EGQQRFEWEFQQQGPGSGGAGSPGSAGGPGSDP

QQRFEWEFQQQ
100


 


IBT209
MASQQRFQWQFQWQFEQQPRGQQRFQWQFQWQFEQQPEGQQRFQWQFQWQFE
23
QQRFQWQFQWQFEQQ
91



QQGPGSDP





 


IBT210
MASQQRFQWQFQWQFEQQPRGQQRFQWQFQWQFEQQPEGQQRFQWQFQWQFE
24
QQRFQWQFQWQFEQQ
91



QQGPGSGGAGSPGSAGGPGSDP





 


IBT212
MASQQRFRWQFQWQFEQQPRGQQRFRWQFQWQFEQQPEGQQRFRWQFQWQFE
25
QQRFRWQFQWQFEQQ
96



QQGPGSGGAGSPGSAGGPGSDP





 


IBT214
MASQQRFRWQFRWQFEQQPRGQQRFQWQFRWQFEQQPEGQQRFRWQFRWQFE
26
QQRFRWQFRWQFEQQ
97



QQGPGSGGAGSPGSAGGPGSDP

QQRFQWQFRWQFEQQ
93


 


IBT216
MASQQRFQWQFRWQFEQQPRGQQRFRWQFRWQFEQQPEGQQRFQWQFRWQFE
27
QQRFQWQFRWQFEQQ
93



QQGPGSGGAGSPGSAGGPGSDP

QQRFRWQFRWQFEQQ
97


 


IBT218
MASQQRFQFQFQFEQQPRGQQRFQFQFQFEQQPEGQQRFQFQFQFEQQGPGSGG
28
QQRFQFQFQFEQQ
88



AGSPGSAGGPGSDP





 


IBT220
MASQQRFRFRFQFEQQPRGQQRFRFQFQFEQQPEGQQRFRFRFQFEQQGPGSGGA
29
QQRFRFRFQFEQQ
95



GSPGSAGGPGSDP

QQRFRFQFQFEQQ
94


 


IBT222
MASQQRFRFQFQFEQQPRGQQRFRFRFQFEQQPEGQQRFRFQFQFEQQGPGSGGA
30
QQRFRFQFQFEQQ
94



GSPGSAGGPGSDP

QQRFRFRFQFEQQ
95


 


IBT223
MASQQRFQWQFEQQPRGQQRFQWQFEQQPRGQQRFQWQFEQQPEGQQRFQWQF
31
QQRFQWQFEQQ
89



EQQGSDP





 


IBT224
MASQQRFQWQFQQQPRGQQRFQWQFQQQPRGQQRFQWQFQQQPEGQQRFQWQ
32
QQRFQWQFQQQ
90



FQQQGSGSDP





 


IBT225
MASQQRFQWQFQQQPRGQQRFQWQFQQQPRGQQRFQWQFQQQPEGQQRFQWQ
33
QQRFQWQFQQQ
90



FQQQGPGSGGAGSPGSAGGPGSGSDP





 


IBT229
MASQQHFQWQFEQQPRGQQHFQWQFEQQPRGQQHFQWQFEQQPEGQQHFQWQ
34
QQHFQWQFEQQ
83



FEQQGSDP





 


IBT230
MASQQHFQWQFEQQPRGQQHFQWQFEQQPRGQQHFQWQFEQQPEGQQHFQWQ
35
QQHFQWQFEQQ
83



FEQQGPGSGGAGSPGSAGGPGSDP





 


IBT232
MASQQHFHWQFEQQPRGQQHFHWQFEQQPRGQQHFHWQFEQQPEGQQHFHWQF
36
QQHFHWQFEQQ
82



EQQGSDP





 


IBT233
MASHQHFHWQFEQQPRGHQHFHWQFEQQPRGHQHFHWQFEQQPEGHQHFHWQF
37
HQHFHWQFEQQ
80



EQQGS





 


IBT239
MASQQRFQWQFEQQPRGQQRFQWQFEQQPRGQQRFQWQFEQQPEGQQRFQWQ
38
QQRFQWQFEQQ
89



FEQQGPGSGGAGSPGSAGGPGSDP





 


IBT241
MASQQHFHWQFEQQPRGQQHFHWQFEQQPRGQQHFHWQFEQQPEGQQHFHWQF
39
QQHFHWQFEQQ
82



EQQGPGSGGAGSPGSAGGPGSDP





 


IBT242
MASHQHFHWQFEQQPRGHQHFHWQFEQQPRGHQHFHWQFEQQPEGHQHFHWQF
40
HQHFHWQFEQQ
80



EQQGPGSGGAGSPGSAGGPGSDP





 


IBT247
MASQQHFHWQFEQQPRGQQHFHWQFEQQPRGQQHFHWQFEQQPRGQQHFHWQF
41
QQHFHWQFEQQ
82



EQQPRRGPGSGGAGSPGSAGGPGS





 


IBT248
MASHQHFHWQFEQQPRGHQHFHWQFEQQPRGHQHFHWQFEQQPRGHQHFHWQF
42
HQHFHWQFEQQ
80



EQQPRRGPGSGGAGSPGSAGGPGS





 


IBT249
MASQQRFQWQFEQQGGAGQGGLGSQGAGQGAGQQRFQWQFEQQGGAGQGGYG
43
QQRFQWQFEQQ
89



GLGSQGAGRGGQGAGQQRFQWQFEQQGGAGQGGYGGLGSQGAGRGGLGGQGAG






QQRFQWQFEQQGPGSGGAGSPGSAGGPGSDP





 


IBT254
MASQQHFHWQFEQQGGAGQGGLGSQGAGQGAGQQHFHWQFEQQGGAGQGGYGG
44
QQHFHWQFEQQ
82



LGSQGAGRGGQGAGQQHFHWQFEQQGGAGQGGYGGLGSQGAGRGGLGGQGAGQ






QHFHWQFEQQGPGSGGAGSPGSAGGPGSDP





 


IBT255
MASHQHFHWQFEQQGGAGQGGLGSQGAGQGAGHQHFHWQFEQQGGAGQGGYGG
45
HQHFHWQFEQQ
80



LGSQGAGRGGQGAGHQHFHWQFEQQGGAGQGGYGGLGSQGAGRGGLGGQGAGH






QHFHWQFEQQGPGSGGAGSPGSAGGPGSDP





 


IBT258
MASQQQFQWQFEQQPEGQQQFQWQFEQQPEGQQQFQWQFEQQGPGSGGAGSPG
46
QQQFQWQFEQQ
85



SAGGPGS





 


IBT259
MASQQQFRWRFEQQPEGQQQFEWEFEQQPRGQQQFRWRFEQQPEGQQQFEWEF
47
QQQFRWRFEQQ
87



EQQGPGSGGAGSPGSAGGPGS

QQQFEWEFEQQ
101


 


IBT260
MASQQHFHWQFEQQPEGQQHFHWQFEQQPRGQQHFHWQFEQQPEGQQHFHWQF
48
QQHFHWQFEQQ
82



EQQGPGSGGAGSPGSAGGPGS





 


IBT261
MASHQHFHWQFEQQPEGHQHFHWQFEQQPRGHQHFHWQFEQQPEGHQHFHWQF
49
HQHFHWQFEQQ
80



EQQGPGSGGAGSPGSAGGPGS





 


IBT262
MASQQRFRWRFQQQGGAGQGGLGSQGAGQGAGQQRFEWEFQQQGGAGQGGYGG
50
QQRFRWRFQQQ
98



LGSQGAGRGGQGAGQQRFRWRFQQQGGAGQGGYGGLGSQGAGRGGLGGQGAGQ

QQRFEWEFQQQ
100



QRFEWEFQQQGPGSGGAGSPGSAGGPG






SDP





 


IBT263
MASQQRFRWRFQQQGGAGQGGLGSQGAGQGAGQQRFEWEFQQQGGAGQGGYGG
51
QQRFRWRFQQQ
98



LGSQGAGRGGQGAGQQRFRWRFQQQGGAGQGGYGGLGSQGAGRGGLGGQGAGQ

QQRFEWEFQQQ
100



QRFEWEFQQQGPGSGGAGSPGSAGGPGSGPGSGGAGSPGSAGGPGSDP





 


IBT282
MASQQHFHWHFQQQPRGQQHFHWHFQQQPEGQQHFHWHFQQQGPGSGGAGSPG
52
QQHFHWHFQQQ
82



SAGGPGS





 


IBT283
MASQQHFHWHFQQQPRGQQKFKWKFQQQPEGQQHFHWHFQQQGPGSGGAGSPG
53
QQHFHWHFQQQ
82



SAGGPGS

QQKFKWKFQQQ
99


 


IBT284
MASQQKFHWHFQQQPRGQQKFHWHFQQQPEGQQKFHWHFQQQGPGSGGAGSPG
54
QQKFHWHFQQQ
84



SAGGPGS





 


IBT287
MASQQKFKWKFQQQPRGQQKFKWKFQQQPEGQQKFKWKFQQQGPGSGGAGSPGS
55
QQKFKWKFQQQ
99



AGGPGS





 


IBT289
MASQQKFKWKFQQQPRGQQHFHWHFQQQPEGQQKFKWKFQQQGPGSGGAGSPGS
56
QQKFKWKFQQQ
99



AGGPGS

QQHFHWHFQQQ
81


 


IBT290
MASQQKFHWKFQQQPRGQQKFHWKFQQQPEGQQKFHWKFQQQGPGSGGAGSPGS
57
QQKFHWKFQQQ
103



AGGPGS





 


IBT294
MASGPCGQQHFHWHFQQQPRGQQKFKWKFQQQPEGQQHFHWHFQQQGPGSGGA
58
QQHFHWHFQQQ
82



GSPGSAGGPGS

QQKFKWKFQQQ
99


 


IBT295
MASGPCGQQKFHWHFQQQPRGQQKFHWHFQQQPEGQQKFHWHFQQQGPGSGGA
59
QQKFHWHFQQQ
84



GSPGSAGGPGS





 


IBT297
MASGPCGQQKFKWKFQQQPRGQQKFKWKFQQQPRGQQKFKWKFQQQPEGQQKFK
60
QQKFKWKFQQQ
99



WKFQKQGPGSGGAGSPGSAGGPGS

QQKFKWKFQKQ
102


 


IBT298
MASGPCGQQRFQWQFEQQPRGQQRFQWQFEQQPRGQQRFQWQFEQQPEGQQRF
61
QQRFQWQFEQQ
89



QWQFEQQGPGSGGAGSPGSAGGPGS





 


IBT299
MASGPCGQQRFQWQFEQQGGAGQGGLGSQGAGQGAGQQRFQWQFEQQGGAGQG
62
QQRFQWQFEQQ
89



GYGGLGSQGAGRGGQGAGQQRFQWQFEQQGGAGQGGYGGLGSQGAGRGGLGGQ






GAGQQRFQWQFEQQGPGSGGAGSPGSAGGPGS





 


IBT310
MASHQHFHWQFEQQGGAGQGGLGSQGAGQGAGHQHFHWQFEQQGGAGQGGYGG
63
HQHFHWQFEQQ
80



LGSQGAGRGGQGAGHQHFHWQFEQQGGAGQGGYGGLGSQGAGRGGLGGQGAGH






QHFHWQFEQQGPRSGGAGSPGSAGGPGSGPGSGGAGSPGSAGGPGSDP





 


IBT311
MASHQHFHWQFEQQGGAGQGGLGSQGAGQGAGHQHFHWQFEQQGGAGQGGYGG
64
HQHFHWQFEQQ
80



LGSQGAGRGGQGAGHQHFHWQFEQQGGAGQGGYGGLGSQGAGRGGLGGQGAGH






QHFHWQFEQQGPRSGAHSPGHSAGHPGSDP





 


IBT312
MASHQHFHWQFEQQGGAGQGGLGSQGAGQGAGHQHFHWQFEQQGGAGQGGYGG
65
HQHFHWQFEQQ
80



LGSQGAGRGGQGAGHQHFHWQFEQQGGAGQGGYGGLGSQGAGRGGLGGQGAGH






QHFHWQFEQQGPRSGGAHSPGSAHGPGSHPGSGHAGSPHSAGHPGSDP





 


IBT313
MASHQHFHWQFEQQGGAGQGGLGSQGAGQGAGHQHFHWQFEQQGGAGQGGYGG
66
HQHFHWQFEQQ
80



LGSQGAGRGGQGAGHQHFHWQFEQQGGAGQGGYGGLGSQGAGRGGLGGQGAGH






QHFHWQFEQQGPGSGASPGSDP





 


IBT314
MASHQHFHWQFEQQGGAGQGGLGSQGAGQGAGHQHFHWQFEQQGGAGQGGYGG
67
HQHFHWQFEQQ
80



LGSQGAGRGGQGAGHQHFHWQFEQQGGAGQGGYGGLGSQGAGRGGLGGQGAGH






QHFHWQFEQQGPHSGHSHGSDP





 


IBT315
MASHQHFHWQFEQQGGAGQGGYGGLGSQGAGRGGQGAGHQHFHWQFEQQGPGS
68
HQHFHWQFEQQ
80



GGAGSPGSAGGPGS





 


IBT316
MASHQHFHWQFEQQGGAGQGGYGGLGSQGAGRGGQGAGHQHFHWQFEQQGGAG
69
HQHFHWQFEQQ
80



QGGYGGLGSQGAGRGGLGGQGAGHQHFHWQFEQQGPGSGGAGSPGSAGGPGS





 


IBT317
MASHQKFHWQFEQQGGAGQGGLGSQGAGQGAGHQKFHWQFEQQGGAGQGGYGG
70
HQKFHWQFEQQ
104



LGSQGAGRGGQGAGHQKFHWQFEQQGGAGQGGYGGLGSQGAGRGGLGGQGAGH






QKFHWQFEQQGPGSGGAGSPGSAGGPGS





 


IBT320
MASHQHFHWQFEQQGGAGQGGLGSQGAGQGAGHQHFHWQFEQQGGAGQGGLGS
71
HQHFHWQFEQQ
80



QGAGQGAGHQHFHWQFEQQGGAGQGGLGSQGAGQGAGHQHFHWQFEQQGPGSG






GAGSPGSAGGPGS





 


IBT321
MASHQHFHWQFEQQGGAGQGGYGGLGSQGAGRGGLGGQGAGHQHFHWQFEQQG
72
HQHFHWQFEQQ
80



GAGQGGYGGLGSQGAGRGGLGGQGAGHQHFHWQFEQQGGAGQGGYGGLGSQGA






GRGGLGGQGAGHQHFHWQFEQQGPGSGGAGSPGSAGGPGS





 


IBT326
MQQRFQWQFEQQNGKTQQRFQWQFEQQGS
73
QQRFQWQFEQQ
89


 


IBT327
MQQRFQWQFEQQYNGKQQRFQWQFEQQGS
74
QQRFQWQFEQQ
89


 


IBT332
MASHQHFHWQFEQQGGAGQGGLGCQGAGQGAGHQHFHWQFEQQGGAGQGGYGG
75
HQHFHWQFEQQ
80



LGCQGAGRGGQGAGHQHFHWQFEQQGGAGQGGYGGLGCQGAGRGGLGGQGAGH






QHFHWQFEQQGPRSGAHSPGHSAGHPGS





 


IBT334
MASHQHFHWQFEQQGPGSGGAGSPGSAGGPGSHDHKNQKETHQRHAAGPGSGGA
76
HQHFHWQFEQQ
80



GSPGSAGGPGSHQHFHWQFEQQGPGSGGAGSPGSAGGPGSTAEIQSSKNPNPHPQ






RSWTNGPGSGGAGSPGSAGGPGSHQHFHWQFEQQGPGSGGAGSPGSAGGPGSTP






PELAHTPHHLAQTRLTDRGPGSGGAGSPGSAGGPGSHQHFHWQFEQQGPGSGGAG






SPGSAGGPGS





 


IBT340
MASHQHFHWQFEQQGGAGQGGLGCQGAGQGAGHQHFHWQFEQQGGAGQGGYGG
77
HQHFHWQFEQQ
80



LGCQGAGRGGQGAGHQHFHWQFEQQGGAGQGGYGGLGCQGAGRGGLGGQGAGH






QHFHWQFEQQGPGSGGAGSPGSAGGPGS





1= core motif(s) underlined.






The multi-functional solubility tags in Table 1 can be defined by the following general structures:

SEQ ID NO: 1—Spacer−[[SEQ ID NO: 1]−[Spacer]m]n 

or

SEQ ID NO: 2—Spacer−[[SEQ ID NO: 2]−[Spacer]m]n 

wherein SEQ ID NO:1 and SEQ ID NO: 2 represent core motifs within each peptide tag;

SEQ ID NO: 1 is

Xaa1-Gln-[Xaa2]p-[Phe-Xaa3-Xaa4-Xaa5]s-Phe-Xaa6-[Xaa7]q-[Gln]r; and

SEQ ID NO: 2 is

Xaa1-Gln-Xaa8-[Xaa4-Xaa8]s-Phe-[Glu-Gln-Gln]r;

wherein

Xaa1=Gln or His;
Xaa2=Gln, Arg, His, or Lys;
Xaa3=Gln, His, Lys, Arg, or Glu;
Xaa4=Trp or Phe;
Xaa5=Gln, His, Lys, Arg or Glu;
Xaa6=Glu, Gln, or Arg;
Xaa7=Gln or Lys;
Xaa8=Asp, Glu, Gln, His, Lys, or Arg;
p, q, and r are independently 0 or 1;
s is an integer ranging from 1 to 5;
n is an integer ranging from 1 to 10;
m=n−1; and
Spacer=a peptide linker ranging from 1 to 100 amino acids in length.
The IBT139-derived variant inclusion body tags in Table 1 were prepared using standard molecular biology techniques. These multi-functional solubility tags were prepared using several approaches including, but not limited to, varying the amino acid composition of the core motifs, changing the number of core motif sequences, selecting different combinations of core motifs, altering the length and composition of the peptide spacers separating the core motifs.
The solubility and insolubility characteristics of the IBTs fused to the soluble peptide of interest (POI) HC263 were evaluated. All the peptides were expressed in E. coli as inclusion bodies indicating their insolubility at neutral pH. Their controllable solubility by using pH (in this case pH 12) was assessed by making a 1-2 mL suspension of fusion peptide in water ( ̃1-2 mg/mL), adjusting the pH to 12 with NaOH, separating the insoluble fraction (pellet) from the soluble fraction (supernatant) by centrifugation (10 min at 15,000×g) and assaying the supernatant by polyacrylamide gel electrophoresis to confirm the solubilization of the peptide. The soluble fraction supernatants were transferred to a new tube and the control of re-insolubilization was assessed by shifting the pH to pH 7.5 by 20 mM Tris 50 mM NaCl, separating the insoluble fraction (pellet) from the soluble fraction (supernatant) by centrifugation (10 min at 15,000×g) and assaying the insoluble fraction (pellet) by polyacrylamide gel electrophoresis to confirm that the fusion peptide was once again insoluble.
All of the multi-functional IBTs tested as fusions to peptide HC263 formed inclusion bodies inside E. coli, could be solubilized at pH 12 and rendered insoluble at pH 7.5 in presence of 50 mM NaCl, thus satisfying the functional feature of controllable solubility of the multi-functional solubility tags.
Example 6
Solubility Tags Providing Additional Functionality
The purpose of this example is to demonstrate that the solubility tags (defined by SEQ ID NO: 1 and SEQ ID NO: 2; Example 5) that are not removed from the peptide of interest (“leave on tags”; LOTs) provide additional functionality to the fusion protein beyond inclusion body formation and controllable solubility during downstream processing. More specifically, the presence of the multi-functional solubility tag can be used to functionalize a target surface by controlling or enhancing deposition of the fusion peptide on a surface via the presence of the multi-functional solubility tag.
The peptide of interest (POI) may be selected to have a binding affinity for a first target material. When coupled to a multi-functional solubility tag providing a binding affinity for a second target material (wherein the first and second materials are different) the resulting fusion peptide enables one to couple the first and second target materials. In one embodiment, the present example demonstrates the ability of fusion proteins comprising the present multi-functional solubility tags to act as bridging agents between the two target materials.
Seven peptides were subjected to a magnetic bead assay described in this example to illustrate the concept that a “leave-on” solubility tag (multi-functional solubility tags and/or fusion peptides comprising such peptide tags) has targeted surface activity. The peptides and their associated functionalities are listed in Table 2.







TABLE 2







Peptides and their associated functionalities










Peptide Name

Target material affinity



(SEQ ID NO:)
Classification
(predicted)
Function(s)





IBT187.1
Multi-functional
Silica
Presence in fusion peptides responsible for


(SEQ ID NO: 4)
Inclusion Body Tag
(e.g. silica particles)
inclusion body formation when coupled to a



(IBT)

peptide of interest.


HC263
Peptide of Interest
Cobalt-nitrilotriacetic acid resin
HC263 contains a hex-his tag (His6) that is


(SEQ ID NO: 6)
(POI)
(e.g. Co-NTA coated magnetic beads)
predicted to bind to Co-NTA resins.


IBT187.HC263
Fusion peptide
Silica particles and Co-NTA coated
IBT187 predicted to bind to silica while HC263


(SEQ ID NO: 8)
(IBT-POI)
magnetic beads
predicted to bind to Co-NTA resin coated





magnetic beads


IBT187.H2-TonB-G3
Fusion peptide
Silica
Same sequence as fusion peptide


(SEQ ID NO: 10)
(IBT-POI)
(e.g., silica particles only)
IBT187.HC263 except lacking the His6 tag.





Predicted to bind to silica only.


IBT233
Multi-functional
Silica
Presence in fusion peptides responsible for


(SEQ ID NO: 37)
Inclusion Body Tag
(e.g., silica particles only)
inclusion body formation when coupled to a



(IBT)

peptide of interest.


IBT233.HC263
Fusion peptide
Silica particles and Co-NTA coated
IBT233 predicted to bind to silica while the His6


(SEQ ID NO: 13)
(IBT-POI)
magnetic beads
portion of HC263 predicted to bind to Co-NTA





resin coated magnetic beads.


HC353
Peptide of Interest
Hair and iron oxide particles (with silica
HC353 contains a hair-binding domain (HP2-


(SEQ ID NO: 298)
(POI)
coating)
TonB-Grey3) linked to an iron oxide pigment





particle binding domain









The seven peptides were individually dissolved in water adjusted to pH 10 with sodium hydroxide at peptide concentrations of 20 μM each as described in Example 4. One mL of the peptide solution was transferred to 1.8-mL microfuge tubes. Silica particles (i.e., Schott glass, approximately 600 nm average diameter particles) were added to a final concentration of 0.5% (w/v). The mixtures were incubated for 60 minutes with agitation. KCl was added to 50 mM concentration to promote insolubility of the “leave on” multi-functional solubility tag and the mixtures were incubated with agitation for an additional 60 minutes. The particles were spun down for 1 minute at 13000 rpm in a centrifuge. The supernatant was discarded and the resulting particle pellet resuspended in 1 mL of pH 10 water. The particles were spun down for 1 min at 13000 rpm in a centrifuge to remove any remaining unbound peptide. The supernatant was discarded and the resulting particle pellet was resuspended in 1 mL of 10 mM MES, pH 5 buffer. Five microliters of magnetic DYNABEADS® TALONTM (magnetic beads coated with Co-NTA resin; Invitrogen, Carlsbad, Calif., Cat #101.01D) were washed according to manufacturer's instructions. The TALONTM technology is comprised of a tetradentate metal chelator which binds to the imidazole rings of a poly histidine peptide chain resin. Approximately 100 μL of silica particle suspension, 5 μL of TALONTM beads and 500 μL of TALONTM binding buffer (50 mM Na-phosphate, pH 8.0, 300 mM NaCl, 0.01% TWEEN®-20) were mixed in a 1.8-mL microfuge tube. After 10 minutes of gentle mixing, the tubes were placed vertically on a magnet (Dynal magnetic particle concentrator, Invitrogen, Cat #120.20D). The magnetic TALONTM beads travel to the center of the magnet as a globule and unbound silica drops to the bottom of the tube. The tubes were rotated around their axis (while still on magnet) to apply shear force on the particles. In the case of peptide-mediated binding of the two particle types to each other, all the particles would travel to the center of the tubes, and could not be broken up via rotating the tubes. There is also a noticeable color change, silica alone is white, TALONTM beads are brown, and the mixed particles are more orange in color. Table 3 below shows which peptides in the magnetic bead assay described in Example 6 were able to facilitate binding between the two types of target materials (i.e., silica particles and Co-NTA coated magnetic particles).







TABLE 3







Description and functions of multi-functional inclusion body tags,


fusion peptides, and peptides of interest.













Observed





Surface-


Peptide ID

Expected
binding


(SEQ ID NO:)
Composition
functions
Activity1





No peptide
—
control
−−−


IBT187.1
Multi-
Silica only
−−−


(SEQ ID NO: 4)
functional



inclusion body



tag (IBT)


HC263
Peptide of
Co-NTA
−−−


(SEQ ID NO: 6)
Interest
coated



(POI)
magnetic




beads


IBT187.HC263
Fusion peptide
Silica
++++


(SEQ ID NO: 8)
(IBT-POI)
(particles)




and Co-NTA




coated




magnetic




beads


IBT187.H2-TonB-
Fusion peptide
Silica only
+


G3
(IBT-POI)


(SEQ ID NO: 10)


IBT233
Multi-
Silica only
−−−


(SEQ ID NO: 37)
functional



inclusion body



tag



(IBT)


IBT233.HC263
Fusion peptide
Silica
++++


(SEQ ID NO: 13)
(IBT-POI)
(particles)




and Co-NTA




coated




magnetic




beads


HC353
Peptide of
Hair and Iron
−−−


(SEQ ID NO:
Interest
Oxide


298)
(POI)
particles





1= Note: ++++ refers to strong binding between particle types that cannot be disrupted by rotating tubes. + refers to very weak binding that can largely be disrupted by rotating tubes. − refers to no observable binding even before rotating tubes.






The results of magnetic bead assay described in Example 6 and Table 3 are also shown in FIG. 3 and indicate that both binding domains (IBT & POI) must be present for the peptide to link the two particle types together.
IBT187.1 and IBT233 are excellent examples of multifunctional “leave on” peptidic solubility tags that (when coupled to a peptide of interest having surface binding activity) facilitate insoluble inclusion body formation, exhibit reversible solubility, and have demonstrated surface binding activity.
Example 7
Fusion Peptide IBT233.HC263 Can Mediate Binding Between Two Target Materials
The purpose of this example is to demonstrate an example of bridging the surfaces of two target materials using a fusion peptide comprising a multi-functional inclusion body tag having affinity for a first target material (a pigment) and a peptide of interest having affinity for a second target material (a body surface, such as hair).
Fusion peptide IBT233.HC263 (SEQ ID NO: 13) contains two engineered structural domains: an inclusion body tag (IBT233; SEQ ID NO: 37)) and a POI (HC263; SEQ ID NO: 6).
The constructs comprising IBT233 and the physio-chemical environment are described in Examples 1-5 for its use as a multi-functional (tri-functional in this case) inclusion body tag. The three functions of IBT233 (when incorporated in a fusion peptide) are:
1. It promotes fusion peptide insolubility in the E. coli cells to facilitate inclusion body formation (Example 2);
2. It provides reversible and controllable solubility for the fusion peptide (Examples 2, 3, 4 and 5); and
3. It provides surface binding activity for silica (Example 6).
In addition to the multi-functional inclusion body tag domain, IBT233.HC263 comprises peptide of interest HC263, which contains two sub-domains; one of which binds to hair and the other hex-His (His6) tag that binds to Co-NTA coated magnetic beads.
This example shows that fusion peptide IBT233.HC263 (SEQ ID NO: 13) can be used to bind pigments to hair. IBT233.HC263 was dissolved in pH 10 water (as described above) at a concentration of 0.5 mg/mL and allowed to gently shake for 1 hour at room temperature ( ̃22° C.). Silica-coated red iron oxide pigments (with an average particle size distribution 200 nm) were added to the IBT233.HC263 containing solution to 0.1% final conc. (w/v) and incubated for 90 min under gentle shaking. KCl was added to 50 mM and the mixture was incubated overnight. The samples were spun down at 10,000 rpm for 2 min in a microfuge, and the supernatant discarded. The mixture was resuspended in pH 10 de-ionized water, vortexed, and spun down again. The supernatant was discarded and the samples were resuspended in 1 mL of 10 mM MES buffer, pH 5. Hair tresses (natural white hair bundle of about 2.5 cm length and 0.5 cm width; International Hair Importers and Products, Bellerose, N.Y.) were added to the microfuge tube containing the fusion peptide-pigment adducts. The hair was incubated for 15 minutes with intermittent vortexing. The tresses were removed and washed under running tap water and gentle embrocation. The hair was dried and the color was measured in X-rite SP64 spectrophotometer, measuring L*, a*, b* values according to Commission Internationale d'Eclairage (CIELAB76).
The experiment was carried out in triplicate, along with no-peptide controls, where everything was carried out identically except no peptide was added to the pigment.







TABLE 4







Color update in the presence of fusion peptide IBT233.HC263











Sample
Color Uptake (ΔE)
Standard Deviation















No peptide (control)
4.9
1.4



IBT233.HC263
26.7
2.1



(SEQ ID NO: 13)










This example shows that the fusion peptide including the inclusion body tag and the hair-binding domain can mediate the binding of a pigment particle to hair and thus demonstrates the multifunctional role of the inclusion body tag.
Example 8
Fusion Peptide IBT255.AuBD Mediates Binding Between Two Target Materials
The purpose of this example is to demonstrate bridging the surfaces of two target materials using a fusion peptide comprising a multi-functional inclusion body tag having affinity for a first target material (glass) and a peptide of interest (POI) having affinity for a second target material (gold particle).
Fusion peptide IBT255.AuBD (SEQ ID NO: 497) was prepared using standard cloning and expression techniques similar to those described in Examples 1-3. IBT255.AuBD contains two engineered structural domains: an inclusion body tag (IBT255; SEQ ID NO: 45) and a POI (AuBD, binding to gold; SEQ ID NO: 496).
The constructs comprising IBT255 and the physio-chemical environment are described in Examples 1-5 for its use as a multi-functional (tri-functional in this case) inclusion body tag. The three functions of IBT255 (when incorporated in a fusion peptide) are:
1. It promotes fusion peptide insolubility in the E. coli cells to facilitate inclusion body formation (Example 2);
2. It provides reversible solubility for the fusion peptide (Examples 2, 3, 4 and 5); and
3. It provides surface binding activity for gold (see Brown, S., (1997) Nat. Biotechnol. 15:269-172).
This example shows that fusion peptide IBT255.AuBD (SEQ ID NO: 497) can be used to bind gold particles to glass. IBT255.AuBD was dissolved in pH 10 water (as described above) at a concentration of 0.5 mg/mL and allowed to gently shake for 1 hour at room temperature ( ̃22° C.). 200 microliters of the solution were spotted onto a microscope glass slide and allowed to incubate for 1 hour at room temperature. The solution was decanted and the glass slide rinsed extensively with distilled water. As a control, the peptide comprised of IBT255 (SEQ ID NO: 45) alone was treated in the same manner as described for the fusion peptide. 200 microliters of a dilute solution (1OD) of 40 nm gold particles in water (Naked Gold, BioAssay Works) were spotted onto the glass slide and incubated for 1 hour at room temperature. The solution was decanted and the glass slide rinsed extensively with distilled water.
Results: On the glass slide incubated with IBT255.AuBD a purple circle (comprised of gold particles of 40 nm size) coinciding with the area of peptide application was visible, indicating the binding of gold particles to the glass. In the case of IBT255 alone, such a purple color was not evident. The experiment shows that IBT255.AuBD is able to anchor gold particles to the glass surface, where IBT255 binds to glass, and the AuBD binds to the gold particles.
Example 9
Design of Cysteine Cross-Linkable Multi-Functional Inclusion Body Tags
Multi-functional inclusion body tags (“IBTs”) with sequences derived from the group of sequences with the general formula shown below were designed as to include cross-linkable cysteine residues in their structure.

SEQ ID NO: 1—Spacer−[[SEQ ID NO: 1]−[Spacer]m]n or  i)

SEQ ID NO: 2—Spacer−[[SEQ ID NO: 2]−[Spacer]m]n  ii)

wherein
SEQ ID NO: 1 is
Xaa1-Gln-[Xaa2]p-[Phe-Xaa3-Xaa4-Xaa5]s-Phe-Xaa6-[Xaa7]q-[Gln]r; and
SEQ ID NO: 2 is
Xaa1-Gln-Xaa8-[Xaa4-Xaa8]s-Phe-[Glu-Gln-Gln]r;
wherein
Xaa1=Gln or His
Xaa2=Gln, Arg, His, or Lys;
Xaa3=Gln, His, Lys, Arg, or Glu;
Xaa4=Trp or Phe
Xaa5=Gln, His, Lys, Arg or Glu;
Xaa6=Glu, Gln, or Arg;
Xaa7=Gln or Lys;
Xaa8=Asp, Glu, Gln, His, Lys, or Arg;
p, q, and r are independently 0 or 1;
s is an integer ranging from 1 to 5;
n is an integer ranging from 1 to 10;
m=n−1; and
Spacer=a peptide linker ranging from 1 to 100 amino acids in length; wherein said spacer comprises at least one cross-linkable cysteine residue.
Examples of IBTs with and without cross-linkable cysteine residues within the spacer element of each structure are provided in Table 5. In particular, IBT331 (SEQ ID NO: 499) and IBT340 (SEQ ID NO: 77) were derived from IBT310 (SEQ ID NO: 63) and IBT 255 (SEQ ID NO: 45) respectively, and included one cysteine residue in each of the three long flexible linkers separating the “insolubilization” amino acid domains (Table 5).







TABLE 5







Examples of multi-functional IBTs with and without cross-linkable cysteine residues


within the spacer elements















SEQ ID


Peptide



NO: (s)


tag

SEQ ID
Core Motif
(core


name
Amino Acid Sequence1
NO:
Sequences(s)
motif(s))














IBT310
MASHQHFHWQFEQQGGAGQGGLGSQGAGQGAGHQHFHWQFEQQGG
63
HQHFHWQFEQQ
80



AGQGGYGGLGSQGAGRGGQGAGHQHFHWQFEQQGGAGQGGYGGLG






SQGAGRGGLGGQGAGHQHFHWQFEQQGPRSGGAGSPGSAGGPGSG






PGSGGAGSPGSAGGPGS





 


IBT331
MASHQHFHWQFEQQGGAGQGGLGCQGAGQGAGHQHFHWQFEQQGG
499
HQHFHWQFEQQ
80



AGQGGYGGLGCQGAGRGGQGAGHQHFHWQFEQQGGAGQGGYGGLG






CQGAGRGGLGGQGAGHQHFHWQFEQQGPRSGGAGSPGSAGGPGSG






PGSGGAGSPGSAGGPGS





 


IBT255
MASHQHFHWQFEQQGGAGQGGLGSQGAGQGAGHQHFHWQFEQQGG
45
HQHFHWQFEQQ
80



AGQGGYGGLGSQGAGRGGQGAGHQHFHWQFEQQGGAGQGGYGGLG






SQGAGRGGLGGQGAGHQHFHWQFEQQGPGSGGAGSPGSAGGPGS





 


IBT340
MASHQHFHWQFEQQGGAGQGGLGCQGAGQGAGHQHFHWQFEQQ
77
HQHFHWQFEQQ
80



GGAGQGGYGGLGCQGAGRGGQGAGHQHFHWQFEQQGGAGQGGYG






GLGCQGAGRGGLGGQGAGHQHFHWQFEQQGPGSGGAGSPGSAGGP






GS





 


IBT332
MASHQHFHWQFEQQGGAGQGGLGCQGAGQGAGHQHFHWQFEQQGG
75
HQHFHWQFEQQ
80



AGQGGYGGLGCQGAGRGGQGAGHQHFHWQFEQQGGAGQGGYGGLG






CQGAGRGGLGGQGAGHQHFHWQFEQQGPRSGAHSPGHSAGHPGS





 


IBT333
MASHQHFHWQFEQQGGAGQGGLGCQGAGQGAGHQHFHWQFEQQGG
500
HQHFHWQFEQQ
80



AGQGGYGGLGCQGAGRGGQGAGHQHFHWQFEQQGGAGQGGYGGLG






CQGAGRGGLGGQGAGHQHFHWQFEQQGPRSGGAHSPGSAHGPGSH






PGSGHAGSPHSAGHPGS





 


IBT341
MASHQHFHWQFEQQGGAGQGGLGCQGAGQGAGHQHFHWQFEQQGG
501
HQHFHWQFEQQ
80



AGQGGYGGLGCQGAGRGGQGAGHQHFHWQFEQQGGAGQGGYGGLG






CQGAGRGGLGGQGAGHQHFHWQFEQQGPHSGHSHGS





 


IBT185
MASPCGQQRFQWQFEQQPCGQQRFQWQFEQQPCGQQRFQWQFEQQ
502
QQRFQWQFEQQ
89



PCGGS





 


IBT186
MASCGQQRFQWQFEQQPRCGQQRFQWQFEQQPECGQQRFQWQFEQ
503
QQRFQWQFEQQ
89



QPCGS





 


IBT292
MASGPCGQQKFKWKFQQQPCGQQKFKWKFQQQPCGQQKFKWKFQQ
504
QQKFKWKFQQQ
99



QPCGPGSGGAGSPGSAGGPGS





 


IBT293
MASGPCGQQKFKWKFQQQPRCGQQKFKWKFQQQPECGQQKFKWKF
505
QQKFKWKFQQQ
99



QQQPCGPGSGGAGSPGSAGGPGS





1= core motif(s) underlined (without bold font); cross-linkable cysteines underlined and in bold font






The HQHFHWQFEQQ (SEQ ID NO: 80) insolubilization (solubility control) (“core motif”) domain (underlined) as well as the cross-linkable cysteines (underlined and in bold font) in the flexible linkers in IBT331 and IBT340 are illustrated in Table 5. IBT255-HC263 (SEQ ID NO: 506) and IBT340-HC263 (SEQ ID NO: 507) are identical in sequence except for the replacement of three serine residues with cysteines; the same is true for IBT310-HC263 (SEQ ID NO: 508) and IBT331-HC263 (SEQ ID NO: 509).
Example 10
Construction of Plasmids for Expression of Peptide Fusions IBT255-HC263, IBT310-HC263, IBT331-HC263, and IBT340-HC263
The purpose of this example is to describe the construction of plasmids encoding the expression of fusions of the hair-binding peptide domain HC263 (SEQ ID NO: 6) downstream of various multifunctional solubility tag (IBT) peptides.
The plasmids encoding the IBT-HC263 constructs were created from plasmid pLR042 (see Example 1) by removing the coding region present between the NdeI/AscI restriction sites and inserting the coding region for the respective fusion peptides IBT-HC263.
The genes encoding for peptides HC263 (SEQ ID NO: 6), IBT310 (SEQ ID NO: 63), IBT331 (SEQ ID NO: 499), IBT255 (SEQ ID NO: 45), and IBT340 (SEQ ID NO: 77) were designed, codon-optimized for E. coli, and synthesized by DNA2.0 (Menlo Park, Calif.). Polynucleotide fragments encoding each IBT were cloned between the NdeI and BamHI restriction sites, and hair-binding peptide HC263 itself cloned in the BamHI and AscI restriction sites as to generate the IBT-HC263 gene fusion. All final constructs had the same general structure:
Arabinose promoter-(NdeI)-IBT-(BamHI)-HC263-(AscI).
The resulting plasmids, pLR805 (encoding fusion peptide IBT310-HC263; SEQ ID NO: 508), pLR880 (encoding fusion peptide IBT331-HC263; SEQ ID NO: 509), pLR712 (encoding fusion peptide IBT255-HC263; SEQ ID NO: 506), and pLR949 (encoding fusion peptide IBT340-HC263; SEQ ID NO: 507) were transferred into the E. coli strain KK2000 to produce strains LR2294, LR2588, LR1955 and LR2931, respectively. KK2000 is a derivative of E. coli strain MG1655 (ATCC 46076TM) wherein the endogenous chromosomal copy of the araBAD operon has been deleted (U.S. Patent Application Publication No. 2010-0159513A1 to Cheng et al., hereby incorporated by reference in its entirety).
Example 11
Production of Cysteine-Containing Inclusion Body Tags
The purpose of this example is to describe the production of fusion peptides between an inclusion body tag (IBT) and a peptide of interest (POI), in this case the hair-binding peptide domain HC263 (SEQ ID NO: 6).
Strains LR2588 expressing IBT331-HC263 (SEQ ID NO: 509) and LR2931 expressing IBT340-HC263 (SEQ ID NO: 507) were each grown at 37° C. for 20 hr in 1 liter autoinduction media (Na2HPO4, 7.1 g; KH2PO4, 6.8 g; (NH4)2SO4, 3.3 g; MgSO4, 0.36 g; Tryptone, 9.2 g; Yeast Extract, 4.6 g; NaCl, 4.6 g; glycerol, 7.5 g; D-glucose, 0.75 g; and L-arabinose, 0.5 g). The two peptides contain cysteine residues and 1 mM DTT was added in the buffers at all subsequent steps to limit their oxidation. Cells were harvested by centrifugation and lysed in 200 mL lysis buffer (50 mM Tris pH 7.5, 10 mM EDTA, 50 mg lysozyme, 1 mM DTT), followed by sonication on ice for 40 seconds. The suspensions were incubated at 37° C. with shaking for 30 min, followed freezing at −20° C. Upon thawing, the inclusion bodies were sonicated on ice for 40 seconds then harvested by centrifugation. The inclusion body pellets were resuspended in 50 mL nuclease treatment buffer (50 mM Tris pH 7.5, 100 mM NaCl, 1 mM DTT, 5 mM MgCl2, 250 Units BenzonaseTM (Sigma, St. Louis, Mo.)). Suspensions were incubated at 37° C. with shaking for 1 hour then inclusion body pellets were recovered by centrifugation and washed with 200 mL of wash solution (50 mM Tris pH 7.5, 100 mM NaCl, 2 mM EDTA, 1 mM DTT), recovered by centrifugation, resuspended in 100 mL water+1 mM DTT and then acidified to pH 1.6 with 1M HCl to solubilize the inclusion bodies. After no less than 15 min, the acidified IB suspensions were centrifuged to remove precipitated proteins while fusion peptides remained soluble at that pH. They were re-precipitated by addition of Tris buffer (10 mM) and NaCl (100 mM) and adjusting the pH to 7.5 with 1 M NaOH, incubation on ice for no less than 30 min. The re-insolubilized inclusion bodies were collected by centrifugation. The inclusion body pellets were washed with 50 mL of water, harvested by centrifugation, and lyophilized.
Strain LR1955 expressing IBT255-HC263 (SEQ ID NO: 506) and strain LR2294 expressing IBT310-HC263 (SEQ ID NO: 508) were grown as described above. Cells were harvested, disrupted and the peptides they each produce purified as described above except that 1 mm DTT was omitted from all buffers as these two peptides do not contain cysteine residues.
IBT310-HC263 formed a gel upon neutralization. Thirty % methanol was added to the neutralized fraction to facilitate precipitation and recovery of IBT310-HC263 by centrifugation. The pellet was then washed with 50 mL of water, harvested by centrifugation, and lyophilized.
This example described the efficient production of fusion peptides between a cysteine-containing inclusion body tag (IBT) and a peptide of interest (POI), in this case the hair-binding peptide domain HC263 (SEQ ID NO:6)
Example 12
Adduct Assembly Process
The purpose of this example is to describe the formation of fusion peptide-target material adducts and how the inclusion of cross-linkable cysteine residues within the fusion constructs results in more durable fusion peptide-target material adducts. The target material exemplified is a pigment material (the adduct formed is a fusion peptide-pigment (the “particulate benefit agent”) adduct).
The peptides used were all insoluble at neutral pH and were dissolved at high pH prior to addition to the pigments. The high pH was slowly lowered to pH 8 via dialysis, which allowed binding of the peptides to the pigment particles.
In each case 0.1 mg/mL of the respective peptide was incubated with a suspension of 0.25 wt % pigment. The pigment used consisted of 4 wt % silica-coated red iron oxide with an isoelectric point of 2 and average particle diameter of about 200 nm. This mixture was brought to pH 12 by addition of sodium hydroxide solution to ensure dissolution of the peptide. In addition, 2 mM of the reducing agent DTT was added. The final mixture (10 mL) was placed in dialysis cassettes (Slide-A-Lyzer Dialysis Cassette, 10000 MWCO, Pierce Biotechnology, Rockford, Ill.) and placed in pH 10 water which had been extensively flushed with nitrogen gas to remove the oxygen from the water. During the 2 hour dialysis step, the pH 10 water was continuously bubbled with nitrogen gas. After 2 hours the cassettes were transferred to pH 8 water, also pre-flushed with nitrogen gas. Again, the pH 8 water was continuously bubbled with nitrogen gas for 2 hours to prevent oxygen from contacting adduct. The cassettes would remain in pH 8 water overnight, and depending on the final conditions, would either be flushed with nitrogen gas (reducing condition), or switched to being flushed with air overnight (oxidizing conditions). The adduct suspension was removed after the overnight dialysis and transferred to a tube for further treatment. If the sample was to remain under reducing conditions, the tube was flushed with nitrogen gas before and during the transfer of the adduct sample.
Example 13
Retention of Peptide on Adduct After pH Challenge
Reduced Versus Oxidized Fusion Peptide IBT331-HC263
The purpose of this example is to illustrate that a fusion peptide construct that contains cysteine residues which are oxidized (after adduct formation) exhibits higher resistance to protein removal from the pigments after a low pH challenge than the equivalent construct that remains under reduced conditions.
Adduct was made with IBT331-HC263 (SEQ ID NO: 509) and silica-coated red iron oxide particles as described in Example 12. One aliquot of the sample was dialyzed overnight under reducing conditions (bubbling with nitrogen gas) and one aliquot was dialyzed under oxidizing conditions (bubbling with air). In each case the pH of the adduct suspension was shifted to pH 2 by addition of hydrochloric acid and mixed by constant rotation of the tubes for 10 minutes. An aliquot of the suspension was removed, spun down, SDS-PAGE gel loading buffer added, and run on an SDS-PAGE gel (FIGS. 1A and 1B).
FIGS. 1A and 1B show that the oxidized sample exhibits higher acid resistance than the reduced sample. The panel of FIG. 1A shows the results of the oxidized sample and the panel of FIG. 1B shows that of the reduced sample. Referring to FIG. 1A, Lane 1 shows the amount of protein bound to the initial adduct prior to the pH shift, lane 2 the corresponding amount of protein in the supernatant. The vast majority of protein is bound to the pigments under these conditions. The equivalent results were found for the reduced sample (FIG. 1B, lanes 5 and 6). Upon low pH challenge of the oxidized sample a small amount of protein was released from the pigments (FIG. 1A, lane 3), but the vast majority remained associated with the pigments (FIG. 1A, lane 4). However, in the case of the reduced sample, the majority of the protein was released from the pigment (FIG. 1B, lane 7), and only a minor proportion remained bound on the pigment (FIG. 1B, lane 8). This experiment shows that allowing the cysteine (Cys) residues to oxidize results in proteins that form a tighter shell around the pigments that are resistant to a low pH challenge.
Example 14
Retention of Peptide on Adduct After pH Challenge
Comparing Cysteine Containing and Non-Cysteine Containing Peptides Under Oxidizing Conditions
This example illustrates that constructs that contain cross-linkable cysteine residues, which are oxidized after adduct formation, exhibit higher resistance to protein removal from the pigments upon a low pH challenge than the equivalent constructs without cysteine residues.
Adducts were made with peptides IBT255-HC263 (SEQ ID NO: 506), IBT310-HC263 (SEQ ID NO: 508), IBT331-HC263 (SEQ ID NO: 509), and IBT340-HC263 (SEQ ID NO: 507), respectively and silica-coated red iron oxide as described in Example 12. The respective samples were dialyzed overnight under oxidizing conditions (bubbling with air). In each case the samples were split into two, where the pH of the adduct suspension of one aliquot was shifted to pH 2 by addition of hydrochloric acid and mixed by constant rotation of the tubes for 10 minutes. The other aliquot was treated identically except there was no addition of hydrochloric acid. An aliquot of each suspension was removed, spun down, SDS-PAGE gel loading buffer added, and run on an SDS-PAGE gel (FIG. 2).
FIG. 2 shows the amount of protein remaining on pigments for each peptide under oxidizing conditions, either including a low pH challenge or not. As can be seen in the samples with no added hydrochloric acid the amount of protein remaining on the pigments is equivalent among all four peptide samples (left lane in panels). However, in the case of the low pH challenge, a significant amount of protein is removed with peptides IBT255-HC263 (SEQ ID NO: 506) and IBT310-HC263 (SEQ ID NO: 508) (right lane in panels), as indicated by the fainter bands remaining. These two proteins contain no cysteine residues in their sequence. Protein remains on the pigments in adduct formed with IBT340-HC263 (SEQ ID NO: 507) and IBT331-HC263 (SEQ ID NO: 509). Similar to Example 13, this experiment shows that fusion peptides containing oxidized Cys residues form a tighter shell around the pigments which are resistant to a low pH challenge.
Example 15
Retention of Peptide on Adduct After Surfactant Challenge
Reduced Versus Oxidized IBT331-HC263
This example illustrates that a construct that contains cross-linkable cysteine (Cys) residues which are oxidized after adduct formation exhibits higher resistance to protein removal from the pigments upon detergent challenge than the equivalent construct that remains under reduced conditions.
Adduct was made with IBT331-HC263 (SEQ ID NO: 509) and silica-coated red iron oxide as described in Example 12. One aliquot of the sample was dialyzed overnight under reducing conditions (bubbling with nitrogen gas) and one aliquot was dialyzed under oxidizing conditions (bubbling with air). In each case the detergent SLES (sodium lauryl ether sulfate) was added to 2% concentration and mixed by constant rotation of the tubes for 10 minutes. An aliquot of the suspension was removed, spun down, SDS-PAGE gel loading buffer added, and run on an SDS-PAGE gel (FIGS. 3A and 3B).
FIGS. 3A and 3B show that the oxidized sample exhibits higher acid resistance than the reduced sample. The panel of FIG. 3A shows the results of the oxidized sample and the panel of FIG. 3B shows that of the reduced sample. Referring to FIG. 3A, lane 1 shows the amount of protein bound to the initial adduct prior to the detergent challenge, lane 2 the corresponding amount of protein in the supernatant. The vast majority of protein is bound to the pigments under these conditions. The equivalent results were found for the reduced sample (FIG. 3B, lanes 5 and 6). Upon detergent challenge of the oxidized sample no detectable amount of protein was released from the pigments (FIG. 3A, lane 4), but the vast majority remained associated with the pigments (FIG. 3A, lane 3). However, in the case of the reduced sample, a portion of protein was released from the pigment (FIG. 3B, lane 8).
This experiment shows that allowing the cysteine residues to oxidize results in peptides that form a tighter shell around the pigments that are more resistant to detergent challenge.
Example 16
Retention of Peptide on Adduct After Surfactant Challenge
Comparing Cys and Non-Cys Containing Peptides Under Oxidizing Conditions
This example illustrates that constructs that contain cysteine residues which are oxidized after adduct formation exhibit higher resistance to protein removal from the pigments upon detergent challenge than the equivalent constructs without cysteine residues.
Adducts were made with peptides IBT255-HC263 (SEQ ID NO: 506), IBT310-HC263 (SEQ ID NO: 508), IBT331-HC263 (SEQ ID NO: 509), and IBT340-HC263 (SEQ ID NO: 507), respectively and silica-coated red iron oxide as described in Example 12. The respective samples were dialyzed overnight under oxidizing conditions (bubbling with air). In each case the samples were split into two, SLES (sodium lauryl ether sulfate) was added to 2% concentration to one aliquot and mixed by constant rotation of the tubes for 10 minutes. The other aliquot was treated identically except there was no addition of SLES. An aliquot of each suspension was removed, spun down, SDS-PAGE gel loading buffer added, and run on an SDS-PAGE gel (FIG. 4).
FIG. 4 shows the amount of protein remaining on pigments for each peptide under oxidizing conditions, either including a detergent challenge or not. As can be seen in the case of no added detergent the amount of protein remaining on the pigments is equivalent among all four peptide samples (left lane in panels). However, in the case of the detergent challenge, a significant amount of protein is removed with peptides IBT255-HC263 (SEQ ID NO: 506) and IBT310-HC263 (SEQ ID NO: 508) (right lane in panels), as indicated by the fainter band remaining. These two proteins contain no cross-linkable cysteine residues in their sequence. Protein remained on the pigments in adduct formed with IBT340-HC263 and IBT331-HC263.
Like Example 15, this experiment shows that containing oxidized Cys residues results in proteins that form a tighter shell around the pigments which are more resistant to a detergent challenge.
Example 17
Retention of Peptide on Adduct After Surfactant Challenge
Different Pigment Types
This example illustrates that a construct containing cross-linkable cysteine residues (i.e., in the spacer segments) which are oxidized after adduct formation exhibits high resistance to protein removal from different types of pigments upon detergent challenge.
Adduct was made with IBT331-HC263 (SEQ ID NO: 509) and pigments as described in Example 12. Three different types of pigments were chosen:
1) silica coated red iron oxide, as described in Example 12;
2) red iron oxide, predicted isoelectric point of 8, approximate size of 300 nm diameter; and
3) silica particles: Schott glass, approximate diameter of 600 nm.
Each of these pigments (at a 0.25% suspension) were incubated with 0.1 mg/mL of IBT331-HC263 (SEQ ID NO: 509) as described in Example 12. The respective samples of pigment with IBT331-HC263 were dialyzed overnight under oxidizing conditions (bubbling with air). In each case SLES (sodium lauryl ether sulfate) was added to 2% concentration and mixed by constant rotation of the tubes for 10 minutes. An aliquot of the suspension was removed, spun down, SDS-PAGE gel loading buffer added, and run on an SDS-PAGE gel (FIG. 5).
FIG. 5 shows that the oxidized sample IBT331-HC263 exhibits high acid resistance with all three types of pigments. In each case all protein remained attached to the pigments after acid challenge, rather than being released into the unbound fraction.
Example 18
Improved Functionality of Cysteine-Cross-Linked Adducts on Hair
This example shows that constructs with cross-linkable (i.e., oxidizable) residues confer higher mechanical/detergent resistance of pigments bound to human hair.
Adducts were made with peptides IBT255-HC263 (SEQ ID NO: 506), IBT310-HC263 (SEQ ID NO: 508), IBT331-HC263 (SEQ ID NO: 509), and IBT340-HC263 (SEQ ID NO: 507), respectively and silica-coated red iron oxide as described in Example 12. HC263 within each construct contains hair binding sequences which will confer pigment binding to human hair. The respective samples were dialyzed overnight under oxidizing conditions (bubbling with air) or reducing conditions. One milliliter of the respective adduct suspensions was transferred to microfuge tubes (tubes under reducing conditions were flushed with nitrogen gas prior and during transfer). Hair tresses (natural white hair bundle of about 2.5 cm in length and 0.5 cm wide; International Hair Importers and Products, Glensdale N.Y.) were added to the microfuge tube containing the adduct. The hair was incubated for 15 minutes with intermittent vortexing. After this stage all the samples were exposed to air, thus allowing potential oxidation of the cysteine residues after the adducts were already bound to hair. The tresses were removed from the tubes and washed under running tap water and gentle embrocation. The hair was dried and the color was measured in X-rite SP64 spectrophotometer, measuring L*, a*, b* values according to Commission Internationale d'Eclairage (CIELAB76)) to obtain the initial color of the hair tresses. L* represents the lightness variable and a* and b* represent the chromaticity coordinates of CIELAB colorspace as defined by the International Commission of Illumination (CIE) (Minolta, Precise Color Communication—Color Control From Feeling to Instrumentation, Minolta Camera Co., 1996).
The hair tresses were treated with 5 shampoo embrocation cycles following the procedure described in U.S. Patent Application Publication Nos. 2010-0158822 and 2010-0158837. In brief, the tresses subjected to shampooing cycles were placed in wells of a 24-well plate. Glass and stainless steel beads (3 mm glass beads×4, 4 mm stain steel beads×1, 6.35 mm glass beads×2) were charged into each well. Approximately 1.0 mL of 0.2% sodium lauryl ether sulfate (SLES) solution was added to each well. The well plate was covered with a flexible SANTOPRENE® thermoplastic elastomer mat and was agitated at high speed on the vortex mixer for 30 sec. The shampoo was removed from the wells by suction. Approximately 4 mL of de-ionized water was added to each well; the plate was agitated at a low speed on the vortex mixer for 5-10 sec. The rinse solution was removed by suction. The tress was thoroughly rinsed under a jet of de-ionized water and subjected to the next shampoo cycle.
After the last shampoo cycle, the tress were dried in air and the retained color was measured again. Overall changes in color were calculated as Delta-E from L*, a* and b* using the formulae

ΔE uptake=√{square root over (((Lu*−L0)^2+(au*−a0)^2+(bu*−b0)^2))}{square root over (((Lu*−L0)^2+(au*−a0)^2+(bu*−b0)^2))}{square root over (((Lu*−L0)^2+(au*−a0)^2+(bu*−b0)^2))}

and

ΔE retention=√{square root over (((Lr*−L0)^2+(ar*−a0)^2+(br*−b0)^2))}{square root over (((Lr*−L0)^2+(ar*−a0)^2+(br*−b0)^2))}{square root over (((Lr*−L0)^2+(ar*−a0)^2+(br*−b0)^2))}

Where, Lu*, au* and bu* are L*, a* and b* values for a sample tress after color uptake, Lr*, ar* and br* are L*, a* and b* values for a sample tress after shampoo cycles, and L0*, a0* and b0* are L*, a* and b* values for untreated natural white hair. The Larger Delta E values are indicative of better color retention. The color update results are provided in Table 6.







TABLE 6







The final ΔE color update values obtained for the samples.














IBT331-
IBT340-



IBT255-
IBT310-
HC263
HC263



HC263
HC263
(Cys)
(Cys)















Color uptake (ΔE)
16
18
23
24


Reduced


conditions


Color uptake (ΔE)
17
15
29
23


Oxidized


conditions









Table 6 results show that constructs containing cross-linkable cysteine residues resulted in higher color retention of pigments on hair tresses. This can be seen for both the reducing as well as the oxidizing conditions. These results indicate that the cysteine residues were able to oxidize after the pigments bound to hair.

## Claims

1. A method comprising:
a) providing a host cell comprising an expressible genetic construct encoding an insoluble fusion peptide comprising at least one first portion and at least one second portion, wherein said first portion comprises a multi-functional solubility tag (MST) and said second portion comprises a peptide of interest (POI); wherein the multi-functional solubility tag (MST) has the general formula of:


SEQ ID NO: 1—Spacer−[[SEQ ID NO: 1]−[Spacer]m]n or  (i)



SEQ ID NO: 2—Spacer−[[SEQ ID NO: 2]−[Spacer]m]n;  (ii)



wherein SEQ ID NO: 1 is Xaa1-Gln-[Xaa2]p-[Phe-Xaa3-Xaa4-Xaa5]s-Phe-Xaa6-[Xaa7]q-[Gin]r; and
SEQ ID NO: 2 is Xaa1-Gln-Xaa8-[Xaa4-Xaa8]s-Phe-[Glu-Gln-Gln]r;
wherein
Xaa1=Gln or His;
Xaa2=Gln, Arg, His, or Lys;
Xaa3=Gln, His, Lys, Arg, or Glu;
Xaa4=Trp or Phe;
Xaa5=Gln, His, Lys, Arg or Glu;
Xaa6=Glu, Gln, or Arg;
Xaa7=Gln or Lys;
Xaa8=Asp, Glu, Gln, His, Lys, or Arg;
p, q, and r are independently 0 or 1;
s is an integer ranging from 1 to 5;
n is an integer ranging from 2 to 10;
m=n or n-1; and

Spacer=a peptide linker ranging from 3 to 60 amino acids in length; wherein said spacer comprises at least one cross-linkable cysteine residue;
b) growing the microbial host cell whereby the insoluble fusion peptide is produced within the host cell in the form of at least one inclusion body;
c) recovering the insoluble fusion peptide from the microbial host cell;
d) subjecting the recovered insoluble fusion peptide of (c) to aqueous reducing conditions having a pH of at least 10 for a period of time to solubilize the insoluble fusion peptide and reduce cross-linkable cysteine residues; whereby an aqueous solution comprising a population of reduced fusion peptides is produced;
e) contacting the aqueous solution comprising the population of reduced fusion peptides of (d) with a first target material whereby a mixture is formed;
f) altering the pH of the mixture of (e) whereby the population of reduced fusion peptides non-covalently binds with the first target material forming fusion peptide-first target material complexes; wherein the binding between the fusion peptides and the first target material is dependent upon, or enhanced by, the presence of the multi-functional solubility tag;
g) subjecting the fusion peptide-first target material complexes of (f) to oxidizing conditions whereby the cysteine residues cross-link; and
h) optionally recovering the product of step (g).

2. The method of claim 1 wherein the multi-functional solubility tags are less than 400 amino acids in length.

3. The method of claim 1 wherein the reducing conditions comprises a pH of at least 11.

4. The method of claim 1 wherein the reducing conditions comprises at least one reducing agent.

5. The method of claim 1 wherein the step of altering of the pH of the aqueous mixture is reducing the pH.

6. The method of claim 5 comprising reducing the pH to 8 or less.

7. The method of claim 5 comprising reducing the pH by dialysis.

8. The method of claim 1 comprising subjecting the fusion peptide-first target material complex to oxidizing conditions in step (g) by dialysis.

9. The method of claim 1 wherein the first target material is a particle having an average particle size ranging from 3 nm to 10 μm as measured by a light scattering method.

10. The method of claim 1 wherein the first portion of the fusion peptide forms a hydrogel and the second portion has affinity for a human tissue or cell surface receptor.

11. The method of claim 10 wherein the second portion having affinity for a human tissue or cell surface receptor comprises at least one arginine-glycine-aspartic acid (RGD) peptide.

12. The method of claim 1 wherein the number of cross-linkable cysteine residues in said MST is at least 3.