cd03358, LbH_WxcM_N_like, WcxM-like, Left-handed parallel beta-Helix (LbH) N-terminal domain: This group is composed of Xanthomonas campestris WcxM and proteins with similarity to the WcxM N-terminal domain. WcxM is thought to be bifunctional, catalyzing both the isomerization and transacetylation reactions of keto-hexoses. It contains an N-terminal LbH domain responsible for the transacetylation function and a C-terminal isomerase domain. The LbH domain contains imperfect tandem repeats of a hexapeptide repeat motif (X-[STAV]-X-[LIV]-[GAED]-X), typical of enzymes with acyltransferase activity.
pfam01713, Smr, Smr domain. This family includes the Smr (Small MutS Related) proteins, and the C-terminal region of the MutS2 protein. It has been suggested that this domain interacts with the MutS1 protein in the case of Smr proteins and with the N-terminal MutS related region of MutS2. This domain exhibits nicking endonuclease activity that might have a role in mismatch repair or genetic recombination. It shows no significant double strand cleavage or exonuclease activity. The full-length human NEDD4-binding protein 2 also has the polynucleotide kinase activity.
cd05253, UDP_GE_SDE_e, UDP glucuronic acid epimerase, extended (e) SDRs. This subgroup contains UDP-D-glucuronic acid 4-epimerase, an extended SDR, which catalyzes the conversion of UDP-alpha-D-glucuronic acid to UDP-alpha-D-galacturonic acid. This group has the SDR's canonical catalytic tetrad and the TGxxGxxG NAD-binding motif of the extended SDRs. Extended SDRs are distinct from classical SDRs. In addition to the Rossmann fold (alpha/beta folding pattern with a central beta-sheet) core region typical of all SDRs, extended SDRs have a less conserved C-terminal extension of approximately 100 amino acids. Extended SDRs are a diverse collection of proteins, and include isomerases, epimerases, oxidoreductases, and lyases; they typically have a TGXXGXXG cofactor binding motif. SDRs are a functionally diverse family of oxidoreductases that have a single domain with a structurally conserved Rossmann fold, an NAD(P)(H)-binding region, and a structurally diverse C-terminal region. Sequence identity between different SDR enzymes is typically in the 15-30% range; they catalyze a wide range of activities including the metabolism of steroids, cofactors, carbohydrates, lipids, aromatic compounds, and amino acids, and act in redox sensing. Classical SDRs have an TGXXX[AG]XG cofactor binding motif and a YXXXK active site motif, with the Tyr residue of the active site motif serving as a critical catalytic residue (Tyr-151, human 15-hydroxyprostaglandin dehydrogenase numbering). In addition to the Tyr and Lys, there is often an upstream Ser and/or an Asn, contributing to the active site; while substrate binding is in the C-terminal region, which determines specificity. The standard reaction mechanism is a 4-pro-S hydride transfer and proton relay involving the conserved Tyr and Lys, a water molecule stabilized by Asn, and nicotinamide. Atypical SDRs generally lack the catalytic residues characteristic of the SDRs, and their glycine-rich NAD(P)-binding motif is often different from the forms normally seen in classical or extended SDRs. Complex (multidomain) SDRs such as ketoreductase domains of fatty acid synthase have a GGXGXXG NAD(P)-binding motif and an altered active site motif (YXXXN). Fungal type ketoacyl reductases have a TGXXXGX(1-2)G NAD(P)-binding motif.
cd05387, BY-kinase, bacterial tyrosine-kinase. Bacterial tyrosine (BY)-kinases catalyze the autophosphorylation on a C-terminal tyrosine cluster and also phosphorylate endogenous protein substrates by using ATP as phosphoryl donor. Besides their capacity to function as tyrosine kinase, most of these proteins are also involved in the production and transport of exopolysaccharides. BY-kinases are involved in a number of physiological processes ranging from stress resistance to pathogenicity.
cd05256, UDP_AE_SDR_e, UDP-N-acetylglucosamine 4-epimerase, extended (e) SDRs. This subgroup contains UDP-N-acetylglucosamine 4-epimerase of Pseudomonas aeruginosa, WbpP, an extended SDR, that catalyzes the NAD+ dependent conversion of UDP-GlcNAc and UDPGalNA to UDP-Glc and UDP-Gal. This subgroup has the characteristic active site tetrad and NAD-binding motif of the extended SDRs. Extended SDRs are distinct from classical SDRs. In addition to the Rossmann fold (alpha/beta folding pattern with a central beta-sheet) core region typical of all SDRs, extended SDRs have a less conserved C-terminal extension of approximately 100 amino acids. Extended SDRs are a diverse collection of proteins, and include isomerases, epimerases, oxidoreductases, and lyases; they typically have a TGXXGXXG cofactor binding motif. SDRs are a functionally diverse family of oxidoreductases that have a single domain with a structurally conserved Rossmann fold, an NAD(P)(H)-binding region, and a structurally diverse C-terminal region. Sequence identity between different SDR enzymes is typically in the 15-30% range; they catalyze a wide range of activities including the metabolism of steroids, cofactors, carbohydrates, lipids, aromatic compounds, and amino acids, and act in redox sensing. Classical SDRs have an TGXXX[AG]XG cofactor binding motif and a YXXXK active site motif, with the Tyr residue of the active site motif serving as a critical catalytic residue (Tyr-151, human 15-hydroxyprostaglandin dehydrogenase numbering). In addition to the Tyr and Lys, there is often an upstream Ser and/or an Asn, contributing to the active site; while substrate binding is in the C-terminal region, which determines specificity. The standard reaction mechanism is a 4-pro-S hydride transfer and proton relay involving the conserved Tyr and Lys, a water molecule stabilized by Asn, and nicotinamide. Atypical SDRs generally lack the catalytic residues characteristic of the SDRs, and their glycine-rich NAD(P)-binding motif is often different from the forms normally seen in classical or extended SDRs. Complex (multidomain) SDRs such as ketoreductase domains of fatty acid synthase have a GGXGXXG NAD(P)-binding motif and an altered active site motif (YXXXN). Fungal type ketoacyl reductases have a TGXXXGX(1-2)G NAD(P)-binding motif.
pfam13568, OMP_b-brl_2, Outer membrane protein beta-barrel domain. This domain is found in a wide range of outer membrane proteins. This domain assumes a membrane bound beta-barrel fold.
pfam05523, FdtA, WxcM-like, C-terminal. This family includes FdtA from Aneurinibacillus thermoaerophilus, which has been characterized as a dtdp-6-deoxy-3,4-keto-hexulose isomerase. It also includes WxcM from Xanthomonas campestris (pv. campestris).
pfam02631, RecX, RecX family. RecX is a putative bacterial regulatory protein. The gene encoding RecX is found downstream of recA, and is thought to interact with the RecA protein.
cd13125, MATE_like_10, Uncharacterized subfamily of the multidrug and toxic compound extrusion (MATE) proteins. This family might function as a translocase for lipopolysaccharides, such as O-antigen. The integral membrane proteins from the MATE family are involved in exporting metabolites across the cell membrane and are responsible for multidrug resistance (MDR) in many bacteria and animals. A number of family members are involved in the synthesis of peptidoglycan components in bacteria.
pfam05523, FdtA, WxcM-like, C-terminal. This family includes FdtA from Aneurinibacillus thermoaerophilus, which has been characterized as a dtdp-6-deoxy-3,4-keto-hexulose isomerase. It also includes WxcM from Xanthomonas campestris (pv. campestris).
pfam12864, DUF3822, Protein of unknown function (DUF3822). This is a family of uncharacterized bacterial proteins. However, structural-similarity searches indicate the family takes on an actin-like ATPase fold.
cd00616, AHBA_syn, 3-amino-5-hydroxybenzoic acid synthase family (AHBA_syn). AHBA_syn family belongs to pyridoxal phosphate (PLP)-dependent aspartate aminotransferase superfamily (fold I). The members of this CD are involved in various biosynthetic pathways for secondary metabolites. Some well studied proteins in this CD are AHBA_synthase, protein product of pleiotropic regulatory gene degT, Arnb aminotransferase and pilin glycosylation protein. The prototype of this family, the AHBA_synthase, is a dimeric PLP dependent enzyme. AHBA_syn is the terminal enzyme of 3-amino-5-hydroxybenzoic acid (AHBA) formation which is involved in the biosynthesis of ansamycin antibiotics, including rifamycin B. Some members of this CD are involved in 4-amino-6-deoxy-monosaccharide D-perosamine synthesis. Perosamine is an important element in the glycosylation of several cell products, such as antibiotics and lipopolysaccharides of gram-positive and gram-negative bacteria. The pilin glycosylation protein encoded by gene pglA, is a galactosyltransferase involved in pilin glycosylation. Additionally, this CD consists of ArnB (PmrH) aminotransferase, a 4-amino-4-deoxy-L-arabinose lipopolysaccharide-modifying enzyme. This CD also consists of several predicted pyridoxal phosphate-dependent enzymes apparently involved in regulation of cell wall biogenesis. The catalytic lysine which is present in all characterized PLP dependent enzymes is replaced by histidine in some members of this CD.
cd04196, GT_2_like_d, Subfamily of Glycosyltransferase Family GT2 of unknown function. GT-2 includes diverse families of glycosyltransferases with a common GT-A type structural fold, which has two tightly associated beta/alpha/beta domains that tend to form a continuous central sheet of at least eight beta-strands. These are enzymes that catalyze the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. Glycosyltransferases have been classified into more than 90 distinct sequence based families.
