pfam06039, Mqo, Malate:quinone oxidoreductase (Mqo). This family consists of several bacterial Malate:quinone oxidoreductase (Mqo) proteins (EC:1.1.99.16). Mqo takes part in the citric acid cycle. It oxidizes L-malate to oxaloacetate and donates electrons to ubiquinone-1 and other artificial acceptors or, via the electron transfer chain, to oxygen. NAD is not an acceptor and the natural direct acceptor for the enzyme is most likely a quinone. The enzyme is therefore called malate:quinone oxidoreductase, abbreviated to Mqo. Mqo is a peripheral membrane protein and can be released from the membrane by addition of chelators.
cd07812, SRPBCC, START/RHO_alpha_C/PITP/Bet_v1/CoxG/CalC (SRPBCC) ligand-binding domain superfamily. SRPBCC domains have a deep hydrophobic ligand-binding pocket; they bind diverse ligands. Included in this superfamily are the steroidogenic acute regulatory protein (StAR)-related lipid transfer (START) domains of mammalian STARD1-STARD15, and the C-terminal catalytic domains of the alpha oxygenase subunit of Rieske-type non-heme iron aromatic ring-hydroxylating oxygenases (RHOs_alpha_C), as well as the SRPBCC domains of phosphatidylinositol transfer proteins (PITPs), Bet v 1 (the major pollen allergen of white birch, Betula verrucosa), CoxG, CalC, and related proteins. Other members of this superfamily include PYR/PYL/RCAR plant proteins, the aromatase/cyclase (ARO/CYC) domains of proteins such as Streptomyces glaucescens tetracenomycin, and the SRPBCC domains of Streptococcus mutans Smu.440 and related proteins.
TIGR00275, TIGR00275, flavoprotein, HI0933 family. The model when searched with a partial length search brings in proteins with a dinucleotide-binding motif (Rossman fold) over the initial 40 residues of the model, including oxidoreductases and dehydrogenases. Partially characterized members include an FAD-binding protein from Bacillus cereus and flavoprotein HI0933 from Haemophilus influenzae. [Unknown function, Enzymes of unknown specificity].
pfam10459, Peptidase_S46, Peptidase S46. Dipeptidyl-peptidase 7 (DPP-7) is the best characterized member of this family. It is a serine peptidase that is located on the cell surface and is predicted to have two N-terminal transmembrane domains.
TIGR02733, similar_to_to_phytoene_dehydrogenase, C-3',4' desaturase CrtD. Members of this family are slr1293, a carotenoid biosynthesis protein which was shown to be the C-3',4' desaturase (CrtD) of myxoxanthophyll biosynthesis in Synechocystis sp. strain PCC 6803, and close homologs (presumed to be functionally equivalent) from other cyanobacteria, where myxoxanthophyll biosynthesis is either known or expected. This enzyme can act on neurosporene and so presumably catalyzes the first step that is committed to myxoxanthophyll. [Biosynthesis of cofactors, prosthetic groups, and carriers, Other].
pfam09835, DUF2062, Uncharacterized protein conserved in bacteria (DUF2062). This domain, found in various prokaryotic proteins, has no known function.
pfam12120, Arr-ms, Rifampin ADP-ribosyl transferase. This protein is found in bacteria. Proteins in this family are typically between 136 to 150 amino acids in length. The opportunistic pathogen Mycobacterium smegmatis is resistant to rifampin because of the presence of a chromosomally encoded rifampin ADP-ribosyltransferase (Arr-ms). Arr-ms is a small enzyme whose activity thus renders rifamycin antibiotics ineffective.
pfam16267, DUF4920, Domain of unknown function (DUF4920). This family consists of uncharacterized proteins around 190 residues in length and is mainly found in various Bacteroides species. The function of this family is unknown.
cd05369, TER_DECR_SDR_a, Trans-2-enoyl-CoA reductase (TER) and 2,4-dienoyl-CoA reductase (DECR), atypical (a) SDR. TTER is a peroxisomal protein with a proposed role in fatty acid elongation. Fatty acid synthesis is known to occur in the both endoplasmic reticulum and mitochondria; peroxisomal TER has been proposed as an additional fatty acid elongation system, it reduces the double bond at C-2 as the last step of elongation. This system resembles the mitochondrial system in that acetyl-CoA is used as a carbon donor. TER may also function in phytol metabolism, reducting phytenoyl-CoA to phytanoyl-CoA in peroxisomes. DECR processes double bonds in fatty acids to increase their utility in fatty acid metabolism; it reduces 2,4-dienoyl-CoA to an enoyl-CoA. DECR is active in mitochondria and peroxisomes. This subgroup has the Gly-rich NAD-binding motif of the classical SDR family, but does not display strong identity to the canonical active site tetrad, and lacks the characteristic Tyr at the usual position. 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 have a 3-glycine N-terminal NAD(P)(H)-binding pattern (typically, TGxxxGxG in classical SDRs and TGxxGxxG in extended SDRs), while substrate binding is in the C-terminal region. A critical catalytic Tyr residue (Tyr-151, human 15-hydroxyprostaglandin dehydrogenase (15-PGDH) numbering), is often found in a conserved YXXXK pattern. In addition to the Tyr and Lys, there is often an upstream Ser (Ser-138, 15-PGDH numbering) and/or an Asn (Asn-107, 15-PGDH numbering) or additional Ser, contributing to the active site. Substrates for these enzymes include sugars, steroids, alcohols, and aromatic compounds. The standard reaction mechanism is a proton relay involving the conserved Tyr and Lys, as well as Asn (or Ser). Some SDR family members, including 17 beta-hydroxysteroid dehydrogenase contain an additional helix-turn-helix motif that is not generally found among SDRs.
cd05266, SDR_a4, atypical (a) SDRs, subgroup 4. Atypical SDRs in this subgroup are poorly defined, one member is identified as a putative NAD-dependent epimerase/dehydratase. Atypical SDRs are distinct from classical SDRs. Members of this subgroup have a glycine-rich NAD(P)-binding motif that is related to, but is different from, the archetypical SDRs, GXGXXG. This subgroup also lacks most of the characteristic active site residues of the SDRs; however, the upstream Ser is present at the usual place, and some potential catalytic residues are present in place of the usual YXXXK active site motif. 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. Atypical SDRs include biliverdin IX beta reductase (BVR-B,aka flavin reductase), NMRa (a negative transcriptional regulator of various fungi), progesterone 5-beta-reductase like proteins, phenylcoumaran benzylic ether and pinoresinol-lariciresinol reductases, phenylpropene synthases, eugenol synthase, triphenylmethane reductase, isoflavone reductases, and others. 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. In addition to the Rossmann fold core region typical of all SDRs, extended SDRs have a less conserved C-terminal extension of approximately 100 amino acids, 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.
The bacterium proteins that are colored denote the protein is present at specific phage-related keywords (such as 'capsid', 'head', 'integrase', 'plate', 'tail', 'fiber', 'coat', 'transposase', 'portal', 'terminase', 'protease' or 'lysin' and 'tRNA')
