cd10802, YdjC_TTHB029_like, Thermus thermophiles TTHB029 and similar proteins. This subfamily is represented by an YdjC-family protein TTHB029 from Thermus thermophilus HB8; it is similar to Escherichia coli YdjC, a hypothetical protein encoded by the celG gene. TTHB029 functions as a homodimer. Each of monomer consists of (beta/alpha)-barrel fold. The molecular function of TTHB029 is unclear.
pfam00583, Acetyltransf_1, Acetyltransferase (GNAT) family. This family contains proteins with N-acetyltransferase functions such as Elp3-related proteins.
pfam01555, N6_N4_Mtase, DNA methylase. Members of this family are DNA methylases. The family contains both N-4 cytosine-specific DNA methylases and N-6 Adenine-specific DNA methylases.
cd06173, MFS_MefA_like, Macrolide efflux protein A and similar proteins of the Major Facilitator Superfamily of transporters. This family is composed of Streptococcus pyogenes macrolide efflux protein A (MefA) and similar transporters, many of which remain uncharacterized. Some members may be multidrug resistance (MDR) transporters, which are drug/H+ antiporters (DHAs) that mediate the efflux of a variety of drugs and toxic compounds, conferring resistance to these compounds. MefA confers resistance to 14-membered macrolides including erythromycin and to 15-membered macrolides. It functions as an efflux pump to regulate intracellular macrolide levels. The MefA-like family belongs to the Major Facilitator Superfamily (MFS) of membrane transport proteins, which are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement.
TIGR03329, Phn_aa_oxid, putative aminophosphonate oxidoreductase. This clade of sequences are members of the pfam01266 family of FAD-dependent oxidoreductases. Characterized proteins within this family include glycerol-3-phosphate dehydrogenase (1.1.99.5), sarcosine oxidase beta subunit (1.5.3.1) and a number of deaminating amino acid oxidases (1.4.-.-). These genes have been consistently observed in a genomic context including genes for the import and catabolism of 2-aminoethylphosphonate (AEP). If the substrate of this oxidoreductase is AEP itself, then it is probably acting in the manner of a deaminating oxidase, resulting in the same product (phosphonoacetaldehyde) as the transaminase PhnW (TIGR02326), but releasing ammonia instead of coupling to pyruvate:alanine. Alternatively, it is reasonable to suppose that the various ABC cassette transporters which are also associated with these loci allow the import of phosphonates closely related to AEP which may not be substrates for PhnW.
smart00344, HTH_ASNC, helix_turn_helix ASNC type. AsnC: an autogenously regulated activator of asparagine synthetase A transcription in Escherichia coli).
cd07092, ALDH_ABALDH-YdcW, Escherichia coli NAD+-dependent gamma-aminobutyraldehyde dehydrogenase YdcW-like. NAD+-dependent, tetrameric, gamma-aminobutyraldehyde dehydrogenase (ABALDH), YdcW of Escherichia coli K12, catalyzes the oxidation of gamma-aminobutyraldehyde to gamma-aminobutyric acid. ABALDH can also oxidize n-alkyl medium-chain aldehydes, but with a lower catalytic efficiency.
cd08267, MDR1, Medium chain dehydrogenases/reductase (MDR)/zinc-dependent alcohol dehydrogenase-like family. This group is a member of the medium chain dehydrogenases/reductase (MDR)/zinc-dependent alcohol dehydrogenase-like family, but lacks the zinc-binding sites of the zinc-dependent alcohol dehydrogenases. The medium chain dehydrogenases/reductase (MDR)/zinc-dependent alcohol dehydrogenase-like family, which contains the zinc-dependent alcohol dehydrogenase (ADH-Zn) and related proteins, is a diverse group of proteins related to the first identified member, class I mammalian ADH. MDRs display a broad range of activities and are distinguished from the smaller short chain dehydrogenases (~ 250 amino acids vs. the ~ 350 amino acids of the MDR). The MDR proteins have 2 domains: a C-terminal NAD(P)-binding Rossmann fold domain of a beta-alpha form and an N-terminal catalytic domain with distant homology to GroES. The MDR group contains a host of activities, including the founding alcohol dehydrogenase (ADH), quinone reductase, sorbitol dehydrogenase, formaldehyde dehydrogenase, butanediol DH, ketose reductase, cinnamyl reductase, and numerous others. The zinc-dependent alcohol dehydrogenases (ADHs) catalyze the NAD(P)(H)-dependent interconversion of alcohols to aldehydes or ketones. Active site zinc has a catalytic role, while structural zinc aids in stability. ADH-like proteins typically form dimers (typically higher plants, mammals) or tetramers (yeast, bacteria), and generally have 2 tightly bound zinc atoms per subunit. The active site zinc is coordinated by a histidine, two cysteines, and a water molecule. The second zinc seems to play a structural role, affects subunit interactions, and is typically coordinated by 4 cysteines.
pfam05899, Cupin_3, Protein of unknown function (DUF861). This family consists of several proteins which seem to be specific to plants and bacteria. The function of this family is unknown.
pfam12146, Hydrolase_4, Serine aminopeptidase, S33. This domain is found in bacteria and eukaryotes and is approximately 110 amino acids in length. It is found in association with pfam00561. The majority of the members in this family carry the exopeptidase active-site residues of Ser-122, Asp-239 and His-269 as in UniProtKB:Q7ZWC2.
pfam07920, DUF1684, Protein of unknown function (DUF1684). The sequences featured in this family are found in hypothetical archaeal and bacterial proteins of unknown function. The region in question is approximately 200 amino acids long.
cd03324, rTSbeta_L-fuconate_dehydratase, Human rTS beta is encoded by the rTS gene which, through alternative RNA splicing, also encodes rTS alpha whose mRNA is complementary to thymidylate synthase mRNA. rTS beta expression is associated with the production of small molecules that appear to mediate the down-regulation of thymidylate synthase protein by a novel intercellular signaling mechanism. A member of this family, from Xanthomonas, has been characterized to be a L-fuconate dehydratase. rTS beta belongs to the enolase superfamily of enzymes, characterized by the presence of an enolate anion intermediate which is generated by abstraction of the alpha-proton of the carboxylate substrate by an active site residue and is stabilized by coordination to the essential Mg2+ ion.
cd07805, FGGY_XK_like_2, uncharacterized xylulose kinase-like proteins; a subgroup of the FGGY family of carbohydrate kinases. This subgroup is composed of uncharacterized proteins with similarity to bacterial D-Xylulose kinases (XK, also known as xylulokinase; EC 2.7.1.17), which catalyze the rate-limiting step in the ATP-dependent phosphorylation of D-xylulose to produce D-xylulose 5-phosphate (X5P) and ADP. The presence of Mg2+ or Mn2+ is required for catalytic activity. D-XK exists as a dimer with an active site that lies at the interface between the N- and C-terminal domains. This model includes both the N-terminal domain, which adopts a ribonuclease H-like fold, and the structurally related C-terminal domain. Members of this subgroup belong to the FGGY family of carbohydrate kinases.
cd06267, PBP1_LacI_sugar_binding-like, ligand binding domain of the LacI transcriptional regulator family belonging to the type 1 periplasmic-binding fold protein superfamily. Ligand binding domain of the LacI transcriptional regulator family belonging to the type 1 periplasmic-binding fold protein superfamily. In most cases, ligands are monosaccharide including lactose, ribose, fructose, xylose, arabinose, galactose/glucose, and other sugars. The LacI family of proteins consists of transcriptional regulators related to the lac repressor. In this case, the domain sugar binding changes the DNA binding activity of the repressor domain.
cd19152, AKR_AKR15A, AKR15A family of aldo-keto reductase. The AKR15 family includes Microbacterium luteolum pyridoxal 4-dehydrogenase (PLD), Pseudomonas sp. D-threo-aldose 1-dehydrogenase (FDH), and similar proteins. PLD (EC1.1.1.107) catalyzes irreversible oxidation of pyridoxal. FDH(EC1.1.1.122), also called (2S,3R)-aldose dehydrogenase, or L-fucose dehydrogenase, catalyzes the oxidation of L-fucose to L-fuconolactone in the presence of NADP(+). It is also active against L-galactose, and to a much lesser degree, D-arabinose. FDH (EC1.1.1.122), also called (2S,3R)-aldose dehydrogenase, or L-fucose dehydrogenase, catalyzes the oxidation of L-fucose to L-fuconolactone in the presence of NADP(+). It is also active against L-galactose, and to a much lesser degree, D-arabinose.
cd12172, PGDH_like_2, Putative D-3-Phosphoglycerate Dehydrogenases, NAD-binding and catalytic domains. Phosphoglycerate dehydrogenases (PGDHs) catalyze the initial step in the biosynthesis of L-serine from D-3-phosphoglycerate. PGDHs come in 3 distinct structural forms, with this first group being related to 2-hydroxy acid dehydrogenases, sharing structural similarity to formate and glycerate dehydrogenases of the D-specific 2-hydroxyacid dehydrogenase superfamily, which also include groups such as L-alanine dehydrogenase and S-adenosylhomocysteine hydrolase. Despite often low sequence identity, these proteins typically have a characteristic arrangement of 2 similar subdomains of the alpha/beta Rossmann fold NAD+ binding form. The NAD+ binding domain is inserted within the linear sequence of the mostly N-terminal catalytic domain, which has a similar domain structure to the internal NAD binding domain. Structurally, these domains are connected by extended alpha helices and create a cleft in which NAD is bound, primarily to the C-terminal portion of the 2nd (internal) domain. Some related proteins have similar structural subdomain but with a tandem arrangement of the catalytic and NAD-binding subdomains in the linear sequence. Many, not all, members of this family are dimeric.
cd20005, PBP1_ABC_sugar_binding-like, monosaccharide ABC transporter substrate-binding protein such as CUT2. Periplasmic sugar-binding domain of uncharacterized ABC-type transport systems that share homology with a family of pentose/hexose sugar-binding proteins of the type 1 periplasmic binding protein superfamily, which consists of two domains connected by a three-stranded hinge. The substrate specificity of this group is not known, but it is predicted to be involved in the transport of sugar-containing molecules and chemotaxis.
cd00530, PTE, Phosphotriesterase (PTE) catalyzes the hydrolysis of organophosphate nerve agents, including the chemical warfare agents VX, soman, and sarin as well as the insecticide paraoxon. PTE exists as a homodimer with one active site per monomer. The active site is located next to a binuclear metal center, at the C-terminal end of a TIM alpha- beta barrel motif. The native enzyme contains two zinc ions at the active site however these can be replaced with other metals such as cobalt, cadmium, nickel or manganese and the enzyme remains active.
cd05233, SDR_c, classical (c) SDRs. SDRs are a functionally diverse family of oxidoreductases that have a single domain with a structurally conserved Rossmann fold (alpha/beta folding pattern with a central beta-sheet), an NAD(P)(H)-binding region, and a structurally diverse C-terminal region. Classical SDRs are typically about 250 residues long, while extended SDRs are approximately 350 residues. Sequence identity between different SDR enzymes are typically in the 15-30% range, but the enzymes share the Rossmann fold NAD-binding motif and characteristic NAD-binding and catalytic sequence patterns. These enzymes 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 prostaglandin dehydrogenase (PGDH) numbering). In addition to the Tyr and Lys, there is often an upstream Ser (Ser-138, PGDH numbering) and/or an Asn (Asn-107, PGDH numbering) 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. Extended SDRs have additional elements in the C-terminal region, and typically have a TGXXGXXG cofactor binding motif. 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. Some atypical SDRs have lost catalytic activity and/or have an unusual NAD(P)-binding motif and missing or unusual active site residues. Reactions catalyzed within the SDR family include isomerization, decarboxylation, epimerization, C=N bond reduction, dehydratase activity, dehalogenation, Enoyl-CoA reduction, and carbonyl-alcohol oxidoreduction.
