SII-SWORD/CoKE huggingface dataset:
RNA polymerase sigma-70, actinobacteria (RNA_pol_sigma70_actinobac)
Type: Family

This group of sigma factors are members of the sigma-70 family (

). They and appear by homology, tree building, bidirectional best hits and (with one exception, a paralog in Thermobifida fusca strain YX) their one-to-a-genome distribution, to represent a conserved family. This family is restricted to the Actinobacteria and each gene examined is followed by an anti-sigma factor in an apparent operon.

The bacterial core RNA polymerase complex, which consists of five subunits, is sufficient for transcription elongation and termination but is unable to initiate transcription. Transcription initiation from promoter elements requires a sixth, dissociable subunit called a sigma factor, which reversibly associates with the core RNA polymerase complex to form a holoenzyme . RNA polymerase recruits alternative sigma factors as a means of switching on specific regulons. Most bacteria express a multiplicity of sigma factors. Two of these factors, sigma-70 (gene rpoD), generally known as the major or primary sigma factor, and sigma-54 (gene rpoN or ntrA) direct the transcription of a wide variety of genes. The other sigma factors, known as alternative sigma factors, are required for the transcription of specific subsets of genes.

With regard to sequence similarity, sigma factors can be grouped into two classes, the sigma-54 and sigma-70 families. Sequence alignments of the sigma70 family members reveal four conserved regions that can be further divided into subregions eg. sub-region 2.2, which may be involved in the binding of the sigma factor to the core RNA polymerase; and sub-region 4.2, which seems to harbor a DNA-binding 'helix-turn-helix' motif involved in binding the conserved -35 region of promoters recognised by the major sigma factors .

The plastids of higher plants originating from an ancestral cyanobacterial endosymbiont also contain sigma factors that are encoded by a small family of nuclear genes. All plastid sigma factors belong to the superfamily of sigmaA/sigma70 and have sequences homologous to the conserved regions 1.2, 2, 3, and 4 of bacterial sigma factors .
RNA polymerase sigma-W, bacillaceae (RNA_pol_sigma-W_bacilli)
Type: Family

The bacterial core RNA polymerase complex, which consists of five subunits, is sufficient for transcription elongation and termination but is unable to initiate transcription. Transcription initiation from promoter elements requires a sixth, dissociable subunit called a sigma factor, which reversibly associates with the core RNA polymerase complex to form a holoenzyme . RNA polymerase recruits alternative sigma factors as a means of switching on specific regulons. Most bacteria express a multiplicity of sigma factors. Two of these factors, sigma-70 (gene rpoD), generally known as the major or primary sigma factor, and sigma-54 (gene rpoN or ntrA) direct the transcription of a wide variety of genes. The other sigma factors, known as alternative sigma factors, are required for the transcription of specific subsets of genes.

With regard to sequence similarity, sigma factors can be grouped into two classes, the sigma-54 and sigma-70 families. Sequence alignments of the sigma70 family members reveal four conserved regions that can be further divided into subregions eg. sub-region 2.2, which may be involved in the binding of the sigma factor to the core RNA polymerase; and sub-region 4.2, which seems to harbor a DNA-binding 'helix-turn-helix' motif involved in binding the conserved -35 region of promoters recognised by the major sigma factors .

The plastids of higher plants originating from an ancestral cyanobacterial endosymbiont also contain sigma factors that are encoded by a small family of nuclear genes. All plastid sigma factors belong to the superfamily of sigmaA/sigma70 and have sequences homologous to the conserved regions 1.2, 2, 3, and 4 of bacterial sigma factors .

This entry represents sigmaW, which is restricted to certain lineages of the order Bacillales.
RNA polymerase sigma-M, bacillaceae (RNA_pol_sigma-M_bacilli)
Type: Family

The bacterial core RNA polymerase complex, which consists of five subunits, is sufficient for transcription elongation and termination but is unable to initiate transcription. Transcription initiation from promoter elements requires a sixth, dissociable subunit called a sigma factor, which reversibly associates with the core RNA polymerase complex to form a holoenzyme . RNA polymerase recruits alternative sigma factors as a means of switching on specific regulons. Most bacteria express a multiplicity of sigma factors. Two of these factors, sigma-70 (gene rpoD), generally known as the major or primary sigma factor, and sigma-54 (gene rpoN or ntrA) direct the transcription of a wide variety of genes. The other sigma factors, known as alternative sigma factors, are required for the transcription of specific subsets of genes.

With regard to sequence similarity, sigma factors can be grouped into two classes, the sigma-54 and sigma-70 families. Sequence alignments of the sigma70 family members reveal four conserved regions that can be further divided into subregions eg. sub-region 2.2, which may be involved in the binding of the sigma factor to the core RNA polymerase; and sub-region 4.2, which seems to harbor a DNA-binding 'helix-turn-helix' motif involved in binding the conserved -35 region of promoters recognised by the major sigma factors .

The plastids of higher plants originating from an ancestral cyanobacterial endosymbiont also contain sigma factors that are encoded by a small family of nuclear genes. All plastid sigma factors belong to the superfamily of sigmaA/sigma70 and have sequences homologous to the conserved regions 1.2, 2, 3, and 4 of bacterial sigma factors .

This family of RNA polymerase sigma factors is restricted to certain lineages of the order Bacillales. This family encompasses at least two distinct sigma factors, as two proteins from this family are found in each of Bacillus anthracis, Bacillus subtilis subsp. subtilis str. 168, and Bacillus licheniformis (although these do not apparently represent the same two sigma factors in each species). One of these proteins is designated as SigM in Bacillus subtilis (

) and is activated by various stressors .
Dimethylsulphoxide reductase, chain B (DMSO_DmsB)
Type: Family

This family consists of the iron-sulphur subunit, or chain B, of the anaerobic dimethyl sulphoxide reductase enzyme. Chains A and B are catalytic, while chain C is a membrane anchor.
ECF RNA polymerase sigma factor BldN-like (BldN-like)
Type: Family

This entry represents a family group of sigma factors predominantly found in actinomycetes, including ECF RNA polymerase sigma factor BldN from Streptomyces coelicolor, which is involved in aerial mycelium formation and required for translation from the bldMp1 promoter .

The bacterial core RNA polymerase complex, which consists of five subunits, is sufficient for transcription elongation and termination but is unable to initiate transcription. Transcription initiation from promoter elements requires a sixth, dissociable subunit called a sigma factor, which reversibly associates with the core RNA polymerase complex to form a holoenzyme . RNA polymerase recruits alternative sigma factors as a means of switching on specific regulons. Most bacteria express a multiplicity of sigma factors. Two of these factors, sigma-70 (gene rpoD), generally known as the major or primary sigma factor, and sigma-54 (gene rpoN or ntrA) direct the transcription of a wide variety of genes. The other sigma factors, known as alternative sigma factors, are required for the transcription of specific subsets of genes.

With regard to sequence similarity, sigma factors can be grouped into two classes, the sigma-54 and sigma-70 families. Sequence alignments of the sigma70 family members reveal four conserved regions that can be further divided into subregions eg. sub-region 2.2, which may be involved in the binding of the sigma factor to the core RNA polymerase; and sub-region 4.2, which seems to harbor a DNA-binding 'helix-turn-helix' motif involved in binding the conserved -35 region of promoters recognised by the major sigma factors .

The plastids of higher plants originating from an ancestral cyanobacterial endosymbiont also contain sigma factors that are encoded by a small family of nuclear genes. All plastid sigma factors belong to the superfamily of sigmaA/sigma70 and have sequences homologous to the conserved regions 1.2, 2, 3, and 4 of bacterial sigma factors .
Pentapeptide MXKDX repeat protein (Penta_MxKDx)
Type: Family

Members of this protein family are small bacterial proteins, each with an N-terminal signal sequence followed by up to 11 imperfect repeats of a pentapeptide. The pentapeptide repeat is usually of the form Met-Xaa-Lys-Asp-Xaa. Family member methionine-rich peptide X, from Dechlorosoma suillum, has been shown to serve as an oxidative stress sink, specifically for chlorite and hypochlorite .
RNA polymerase sigma-V type (RNA_pol_sigma-V)
Type: Family

The bacterial core RNA polymerase complex, which consists of five subunits, is sufficient for transcription elongation and termination but is unable to initiate transcription. Transcription initiation from promoter elements requires a sixth, dissociable subunit called a sigma factor, which reversibly associates with the core RNA polymerase complex to form a holoenzyme . RNA polymerase recruits alternative sigma factors as a means of switching on specific regulons. Most bacteria express a multiplicity of sigma factors. Two of these factors, sigma-70 (gene rpoD), generally known as the major or primary sigma factor, and sigma-54 (gene rpoN or ntrA) direct the transcription of a wide variety of genes. The other sigma factors, known as alternative sigma factors, are required for the transcription of specific subsets of genes.

With regard to sequence similarity, sigma factors can be grouped into two classes, the sigma-54 and sigma-70 families. Sequence alignments of the sigma70 family members reveal four conserved regions that can be further divided into subregions eg. sub-region 2.2, which may be involved in the binding of the sigma factor to the core RNA polymerase; and sub-region 4.2, which seems to harbor a DNA-binding 'helix-turn-helix' motif involved in binding the conserved -35 region of promoters recognised by the major sigma factors .

The plastids of higher plants originating from an ancestral cyanobacterial endosymbiont also contain sigma factors that are encoded by a small family of nuclear genes. All plastid sigma factors belong to the superfamily of sigmaA/sigma70 and have sequences homologous to the conserved regions 1.2, 2, 3, and 4 of bacterial sigma factors .

This group of sigma factors appear by homology, tree building, bidirectional best hits and one-to-a-genome distribution, to represent a conserved family. This entry is found in certain Bacillus and Clostridium species.
TMAO reductase system, periplasmic protein TorT (TMAO_TorT)
Type: Family

Periplasmic protein TorT, together with the TorS/TorR histidine kinase/response regulator system, regulates expression of the torCAD operon, which encodes the trimethylamine N-oxide (TMAO) reductase system . TorT appears to bind TMAO or related compounds, and is predicted to be involved in signal transduction and/or substrate transport . TorT shows homology to a periplasmic D-ribose binding protein.
Signal transduction histidine kinase, TMAO sensor TorS (Sig_transdc_His_kinase_TorS)
Type: Family

This entry represents TorS proteins, which are part of a regulatory system for the torCAD operon that encodes the pterin molybdenum cofactor-containing enzyme trimethylamine-N-oxide (TMAO) reductase (TorA), a cognate chaperone (TorD), and a penta-haem cytochrome (TorC). TorS works together with the inducer-binding protein TorT and the response regulator TorR. TorS contains histidine kinase ATPase (

), HAMP (

), phosphoacceptor (

), and phosphotransfer (

) domains and a response regulator receiver domain (

).

Signal transducing histidine kinases are the key elements in two-component signal transduction systems, which control complex processes such as the initiation of development in microorganisms . Examples of histidine kinases are EnvZ, which plays a central role in osmoregulation , and CheA, which plays a central role in the chemotaxis system . Histidine kinases usually have an N-terminal ligand-binding domain and a C-terminal kinase domain, but other domains may also be present. The kinase domain is responsible for the autophosphorylation of the histidine with ATP, the phosphotransfer from the kinase to an aspartate of the response regulator, and (with bifunctional enzymes) the phosphotransfer from aspartyl phosphate back to ADP or to water . The kinase core has a unique fold, distinct from that of the Ser/Thr/Tyr kinase superfamily.

Two-component signal transduction systems enable bacteria to sense, respond, and adapt to a wide range of environments, stressors, and growth conditions . Some bacteria can contain up to as many as 200 two-component systems that need tight regulation to prevent unwanted cross-talk . These pathways have been adapted to response to a wide variety of stimuli, including nutrients, cellular redox state, changes in osmolarity, quorum signals, antibiotics, and more . Two-component systems are comprised of a sensor histidine kinase (HK) and its cognate response regulator (RR) . The HK catalyses its own auto-phosphorylation followed by the transfer of the phosphoryl group to the receiver domain on RR; phosphorylation of the RR usually activates an attached output domain, which can then effect changes in cellular physiology, often by regulating gene expression. Some HK are bifunctional, catalysing both the phosphorylation and dephosphorylation of their cognate RR. The input stimuli can regulate either the kinase or phosphatase activity of the bifunctional HK.

A variant of the two-component system is the phospho-relay system. Here a hybrid HK auto-phosphorylates and then transfers the phosphoryl group to an internal receiver domain, rather than to a separate RR protein. The phosphoryl group is then shuttled to histidine phosphotransferase (HPT) and subsequently to a terminal RR, which can evoke the desired response .
RNA polymerase sigma-70, ECF type (RNA_pol_sigma-70_ECF)
Type: Family

The bacterial core RNA polymerase complex, which consists of five subunits, is sufficient for transcription elongation and termination but is unable to initiate transcription. Transcription initiation from promoter elements requires a sixth, dissociable subunit called a sigma factor, which reversibly associates with the core RNA polymerase complex to form a holoenzyme . RNA polymerase recruits alternative sigma factors as a means of switching on specific regulons. Most bacteria express a multiplicity of sigma factors. Two of these factors, sigma-70 (gene rpoD), generally known as the major or primary sigma factor, and sigma-54 (gene rpoN or ntrA) direct the transcription of a wide variety of genes. The other sigma factors, known as alternative sigma factors, are required for the transcription of specific subsets of genes.

With regard to sequence similarity, sigma factors can be grouped into two classes, the sigma-54 and sigma-70 families. Sequence alignments of the sigma70 family members reveal four conserved regions that can be further divided into subregions eg. sub-region 2.2, which may be involved in the binding of the sigma factor to the core RNA polymerase; and sub-region 4.2, which seems to harbor a DNA-binding 'helix-turn-helix' motif involved in binding the conserved -35 region of promoters recognised by the major sigma factors .

The plastids of higher plants originating from an ancestral cyanobacterial endosymbiont also contain sigma factors that are encoded by a small family of nuclear genes. All plastid sigma factors belong to the superfamily of sigmaA/sigma70 and have sequences homologous to the conserved regions 1.2, 2, 3, and 4 of bacterial sigma factors .

This group of sigma factors appear by homology, tree building and bidirectional best hits, to represent a conserved family. This entry is found in a limited number of bacterial lineages and includes apparent paralogous expansion in Streptomyces coelicolor (strain A3(2)), and multiple copies in Mycobacterium smegmatis (strain ATCC 700084/mc(2)155), Streptomyces avermitilis MA-4680 and Nocardia farcinica IFM 10152.
RNA polymerase sigma-Z type (RNA_pol_sigma-Z)
Type: Family

This entry is a group of RNA polymerase sigma factors where one of the members is designated as SigZ in Bacillus subtilis . This group has a very sporadic distribution, B. subtilis, for instance, being the only sequenced strain of Bacilli with a member Dechloromonas aromatica (strain RCB), that appears to have two of these sigma factors. A member of which appears on a plasmid found in Photobacterium profundum SS9 and Vibrio fischeri (strain ATCC 700601 / ES114), where a second one is chromosomally encoded.
RNA polymerase sigma-G type, actinobacteria (RNA_pol_sigma-G_actinobac)
Type: Family

The bacterial core RNA polymerase complex, which consists of five subunits, is sufficient for transcription elongation and termination but is unable to initiate transcription. Transcription initiation from promoter elements requires a sixth, dissociable subunit called a sigma factor, which reversibly associates with the core RNA polymerase complex to form a holoenzyme . RNA polymerase recruits alternative sigma factors as a means of switching on specific regulons. Most bacteria express a multiplicity of sigma factors. Two of these factors, sigma-70 (gene rpoD), generally known as the major or primary sigma factor, and sigma-54 (gene rpoN or ntrA) direct the transcription of a wide variety of genes. The other sigma factors, known as alternative sigma factors, are required for the transcription of specific subsets of genes.

With regard to sequence similarity, sigma factors can be grouped into two classes, the sigma-54 and sigma-70 families. Sequence alignments of the sigma70 family members reveal four conserved regions that can be further divided into subregions eg. sub-region 2.2, which may be involved in the binding of the sigma factor to the core RNA polymerase; and sub-region 4.2, which seems to harbor a DNA-binding 'helix-turn-helix' motif involved in binding the conserved -35 region of promoters recognised by the major sigma factors .

The plastids of higher plants originating from an ancestral cyanobacterial endosymbiont also contain sigma factors that are encoded by a small family of nuclear genes. All plastid sigma factors belong to the superfamily of sigmaA/sigma70 and have sequences homologous to the conserved regions 1.2, 2, 3, and 4 of bacterial sigma factors .

This group of sigma factors appear by homology, tree building, bidirectional best hits and one-to-a-genome distribution and represent a conserved family.
Hydroxyisourate hydrolase (Hydroxyisourate_hydrolase)
Type: Family

Members of this family, hydroxyisourate hydrolase, represent a distinct clade of transthyretin-related proteins. Bacterial members typically are encoded next to ureidoglycolate hydrolase and often near either xanthine dehydrogenase or xanthine/uracil permease genes and have been demonstrated to have hydroxyisourate hydrolase activity . In eukaryotes, a clade separate from the transthyretins (a family of thyroid-hormone binding proteins) has also been shown to have HIU hydrolase activity in urate catabolizing organisms . Transthyretin, then, would appear to be the recently diverged paralog of the more ancient HIUH family.
Xanthine dehydrogenase, small subunit (Xanthine_DH_ssu)
Type: Domain

Members of this protein are the small subunit (or, in eukaryotes, the N-terminal domain) of xanthine dehydrogenase, an enzyme of purine catabolism via urate . The small subunit contains both an FAD and a 2Fe-2S cofactor. Aldehyde oxidase (retinal oxidase) appears to have arisen as a neofunctionalisation among xanthine dehydrogenases in eukaryotes.
Xanthine dehydrogenase accessory protein XdhC (Xanthine_DH_XdhC)
Type: Family

Members of this family are the accessory protein XdhC, found in bacteria, that is responsible for insertion of the molybdenum cofactor into the xanthine dehydrogenase large chain, XdhB. This protein is not part of the mature xanthine dehydrogenase. Xanthine dehydrogenase is an enzyme for purine catabolism, from other purines to xanthine to urate to further breakdown products.
Xanthine dehydrogenase, molybdopterin binding subunit (Xanthine_DH_Mopterin-bd_su)
Type: Domain

Members of this entry are the molybdopterin-containing large subunit of xanthine dehydrogenase (or, in, eukaryotes, the molybdopterin-binding domain) and those enzymes that reduces the purine pool by catabolizing xanthine to urate. This entry contains primarily bacterial sequences; it does not manage to include all eukaryotic xanthine dehydrogenases and thereby discriminate them from the closely related enzyme aldehyde dehydrogenase.
Signal transduction histidine kinase, phosphate regulon sensor PhoR (Sig_transdc_His_kinase_PhoR)
Type: Family

Two-component signal transduction systems enable bacteria to sense, respond, and adapt to a wide range of environments, stressors, and growth conditions . Some bacteria can contain up to as many as 200 two-component systems that need tight regulation to prevent unwanted cross-talk . These pathways have been adapted to response to a wide variety of stimuli, including nutrients, cellular redox state, changes in osmolarity, quorum signals, antibiotics, and more . Two-component systems are comprised of a sensor histidine kinase (HK) and its cognate response regulator (RR) . The HK catalyses its own auto-phosphorylation followed by the transfer of the phosphoryl group to the receiver domain on RR; phosphorylation of the RR usually activates an attached output domain, which can then effect changes in cellular physiology, often by regulating gene expression. Some HK are bifunctional, catalysing both the phosphorylation and dephosphorylation of their cognate RR. The input stimuli can regulate either the kinase or phosphatase activity of the bifunctional HK.

A variant of the two-component system is the phospho-relay system. Here a hybrid HK auto-phosphorylates and then transfers the phosphoryl group to an internal receiver domain, rather than to a separate RR protein. The phosphoryl group is then shuttled to histidine phosphotransferase (HPT) and subsequently to a terminal RR, which can evoke the desired response .

Signal transducing histidine kinases are the key elements in two-component signal transduction systems, which control complex processes such as the initiation of development in microorganisms . Examples of histidine kinases are EnvZ, which plays a central role in osmoregulation , and CheA, which plays a central role in the chemotaxis system . Histidine kinases usually have an N-terminal ligand-binding domain and a C-terminal kinase domain, but other domains may also be present. The kinase domain is responsible for the autophosphorylation of the histidine with ATP, the phosphotransfer from the kinase to an aspartate of the response regulator, and (with bifunctional enzymes) the phosphotransfer from aspartyl phosphate back to ADP or to water . The kinase core has a unique fold, distinct from that of the Ser/Thr/Tyr kinase superfamily.

This entry represents the regulatory histidine kinases PhoR that are associated with the phosphate ABC transporter found in most Proteobacteria, and related proteins from Gram-positive organisms are excluded. The phoR gene usually is adjacent to the response regulator phoB gene (

).