pfam16571, FBP_C, FBP C-terminal treble-clef zinc-finger. FBP_C is a family from the C terminal end of fibronectin-binding proteins. It forms an extended four-cysteine zinc-finger with a unique structural fold. Fibronectin-binding proteins bind to elongation factor G - EF-G, which is mediated by the zinc-finger binding to the C-terminus of EF-G. FBPs release ribosomes by competing with them for EF-G.
cd03316, MR_like, Mandelate racemase (MR)-like subfamily of the enolase superfamily. Enzymes of this subgroup share three conserved carboxylate ligands for the essential divalent metal ion (usually Mg2+), two aspartates and a glutamate, and conserved catalytic residues, a Lys-X-Lys motif and a conserved histidine-aspartate dyad. Members of the MR subgroup are mandelate racemase, D-glucarate/L-idarate dehydratase (GlucD), D-altronate/D-mannonate dehydratase , D-galactonate dehydratase (GalD) , D-gluconate dehydratase (GlcD), and L-rhamnonate dehydratase (RhamD).
pfam07100, ASRT, Anabaena sensory rhodopsin transducer. The family of bacterial Anabaena sensory rhodopsin transducers are likely to bind sugars or related metabolites. The entire protein is comprised of a single globular domain with an eight-stranded beta-sandwich fold. There are a few characteristics which define this beta-sandwich fold as being distinct from other so-named folds, and these are: 1) a well conserved tryptophan, usually following a polar residue, present at the start of the first strand; this tryptophan appears to be central to a hydrophobic interaction required to hold the two beta-sheets of the sandwich together, and 2) a nearly absolutely conserved asparagine located at the end of the second beta-strand, that hydrogen bonds with the backbone carbonyls of the residues 2 and 4 positions downstream from it, thereby stabilizing the characteristic tight turn between strands 2 and 3 of the structure.
cd00542, Ntn_PVA, Penicillin V acylase (PVA), also known as conjugated bile salt acid hydrolase (CBAH), catalyzes the hydrolysis of penicillin V to yield 6-amino penicillanic acid (6-APA), an important key intermediate of semisynthetic penicillins. PVA has an N-terminal nucleophilic cysteine, as do other members of the Ntn hydrolase family to which PVA belongs. This nucleophilic cysteine is exposed by post-translational prossessing of the PVA precursor. PVA forms a homotetramer.
cd17359, MFS_XylE_like, D-xylose-proton symporter and similar transporters of the Major Facilitator Superfamily. This subfamily includes bacterial transporters such as D-xylose-proton symporter (XylE or XylT), arabinose-proton symporter (AraE), galactose-proton symporter (GalP), major myo-inositol transporter IolT, glucose transport protein, putative metabolite transport proteins YfiG, YncC, and YwtG, and similar proteins. The symporters XylE, AraE, and GalP facilitate the uptake of D-xylose, arabinose, and galactose, respectively, across the boundary membrane with the concomitant transport of protons into the cell. IolT is involved in polyol metabolism and myo-inositol degradation into acetyl-CoA. The XylE-like subfamily belongs to the Glucose transporter -like (GLUT-like) family of the Major Facilitator Superfamily (MFS) of membrane transport proteins. MFS proteins are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement.
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.
cd01086, MetAP1, Methionine Aminopeptidase 1. E.C. 3.4.11.18. Also known as methionyl aminopeptidase and Peptidase M. Catalyzes release of N-terminal amino acids, preferentially methionine, from peptides and arylamides.
