cd16013, AcpA, acid phosphatase A. Acid phosphatase A catalyzes the hydrolysis reaction via a phosphoseryl intermediate to produce inorganic phosphate and the corresponding alcohol, optimally at low pH. AcpA hydrolyzes a variety of substrates, including p-nitrophenylphosphate (pNPP), p-nitrophenylphosphorylcholine (pNPPC), peptides containing phosphotyrosine, inositol phosphates, AMP, ATP, fructose 1,6-bisphosphate, glucose and fructose 6-phosphates, NADP, and ribose 5-phosphate. AcpA is distinct from histidine ACPs and purple ACPs, as well as class A, B, and C bacterial nonspecific ACPs.
pfam04185, Phosphoesterase, Phosphoesterase family. This family includes both bacterial phospholipase C enzymes EC:3.1.4.3, but also eukaryotic acid phosphatases EC:3.1.3.2.
cd01637, IMPase_like, Inositol-monophosphatase-like domains. This family of phosphatases is dependent on bivalent metal ions such as Mg++, and many members are inhibited by Li+ (which is thought to displace a bivalent ion in the active site). Substrates include fructose-1,6-bisphosphate, inositol poly- and monophosphates, PAP and PAPS, sedoheptulose-1,7-bisphosphate and probably others.
cd11555, SLC-NCS1sbd_u1, uncharacterized nucleobase-cation-symport-1 (NCS1) transporter subfamily; solute-binding domain. NCS1s are essential components of salvage pathways for nucleobases and related metabolites; their known substrates include allantoin, uracil, thiamine, and nicotinamide riboside. NCS1s belong to a superfamily which also contains the solute carrier 5 family sodium/glucose transporters (SLC5s), and solute carrier 6 family neurotransmitter transporters (SLC6s).
cd04690, Nudix_Hydrolase_31, Members of the Nudix hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue nudix motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of nudix hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the nudix hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance & "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.
TIGR01073, ATP-dependent_DNA_helicase_PcrA, ATP-dependent DNA helicase PcrA. Designed to identify pcrA members of the uvrD/rep subfamily. [DNA metabolism, DNA replication, recombination, and repair].
TIGR04046, predicted_flavoprotein_involved_in_K+_transport, flavin-dependent oxidoreductase, MSMEG_0569 family. Members of this protein family belong to a conserved seven-gene biosynthetic cluster found sparsely in Cyanobacteria, Proteobacteria, and Actinobacteria. Distant homologies to characterized proteins suggest that members are enzymes dependent on a flavinoid cofactor.
TIGR02696, polyribonucleotide_nucleotidyltransferase, guanosine pentaphosphate synthetase I/polynucleotide phosphorylase. Sohlberg, et al. present characterization of two proteins from Streptomyces coelicolor. The protein in this family was shown to have poly(A) polymerase activity and may be responsible for polyadenylating RNA in this species. Reference 2 showed that a nearly identical plasmid-encoded protein from Streptomyces antibioticus is a bifunctional enzyme that acts also as a guanosine pentaphosphate synthetase.
cd11020, CuRO_1_CuNIR, Cupredoxin domain 1 of Copper-containing nitrite reductase. Copper-containing nitrite reductase (CuNIR), which catalyzes the reduction of NO2- to NO, is the key enzyme in the denitrification process in denitrifying bacteria. CuNIR contains at least one type 1 copper center and a type 2 copper center, which serves as the active site of the enzyme. A histidine, bound to the Type 2 Cu center, is responsible for binding and reducing nitrite. A Cys-His bridge plays an important role in facilitating rapid electron transfer from the type 1 center to the type 2 center. A reduced type I blue copper protein (pseudoazurin) was found to be a specific electron transfer donor for the copper-containing NIR in bacteria Alcaligenes faecalis.
pfam04655, APH_6_hur, Aminoglycoside/hydroxyurea antibiotic resistance kinase. The aminoglycoside phosphotransferases achieve inactivation of their antibiotic substrates by phosphorylation utilising ATP. Likewise hydroxyurea is inactivated by phosphorylation of the hydroxy group in the hydroxylamine moiety.
cd02432, Nodulin-21_like_1, Nodulin-21 and CCC1-related protein family. Nodulin-21_like_1: This is a family of proteins closely related to nodulin-21, a plant nodule-specific protein that may be involved in symbiotic nitrogen fixation. This family is also related to CCC1, a yeast vacuole transmembrane protein that functions as an iron and manganese transporter. .
pfam03993, DUF349, Domain of Unknown Function (DUF349). This domain is found singly or as up to five tandem repeats in a small set of bacterial proteins. There are two or three alpha-helices, and possibly a beta-strand.
TIGR03182, Pyruvate_dehydrogenase_E1_component_subunit_alpha, pyruvate dehydrogenase E1 component, alpha subunit. Members of this protein family are the alpha subunit of the E1 component of pyruvate dehydrogenase (PDH). This model represents one branch of a larger family that E1-alpha proteins from 2-oxoisovalerate dehydrogenase, acetoin dehydrogenase, another PDH clade, etc. [Energy metabolism, Pyruvate dehydrogenase].
cd00317, cyclophilin, cyclophilin: cyclophilin-type peptidylprolyl cis- trans isomerases. This family contains eukaryotic, bacterial and archeal proteins which exhibit a peptidylprolyl cis- trans isomerases activity (PPIase, Rotamase) and in addition bind the immunosuppressive drug cyclosporin (CsA). Immunosuppression in vertebrates is believed to be the result of the cyclophilin A-cyclosporin protein drug complex binding to and inhibiting the protein-phosphatase calcineurin. PPIase is an enzyme which accelerates protein folding by catalyzing the cis-trans isomerization of the peptide bonds preceding proline residues. Cyclophilins are a diverse family in terms of function and have been implicated in protein folding processes which depend on catalytic /chaperone-like activities. This group contains human cyclophilin 40, a co-chaperone of the hsp90 chaperone system; human cyclophilin A, a chaperone in the HIV-1 infectious process and; human cyclophilin H, a component of the U4/U6 snRNP, whose isomerization or chaperoning activities may play a role in RNA splicing. .
cd06456, M3A_DCP, Peptidase family M3, dipeptidyl carboxypeptidase (DCP). Peptidase family M3 dipeptidyl carboxypeptidase (DCP; Dcp II; peptidyl dipeptidase; EC 3.4.15.5). This metal-binding M3A family also includes oligopeptidase A (OpdA; EC 3.4.24.70). DCP cleaves dipeptides off the C-termini of various peptides and proteins, the smallest substrate being N-blocked tripeptides and unblocked tetrapeptides. DCP from Escherichia coli is inhibited by the anti-hypertensive drug captopril, an inhibitor of the mammalian angiotensin converting enzyme (ACE, also called peptidyl dipeptidase A). OpdA may play a specific role in the degradation of signal peptides after they are released from precursor forms of secreted proteins. It can also cleave N-acetyl-L-Ala. This family also includes Arabidopsis thaliana organellar oligopeptidase OOP (At5g65620), which plays a role in targeting peptide degradation in mitochondria and chloroplasts; it degrades peptide substrates that are between 8 to 23 amino acid residues, and shows a weak preference for hydrophobic residues (F/L) at the P1 position.
pfam05140, ResB, ResB-like family. This family includes both ResB and cytochrome c biogenesis proteins. Mutations in ResB indicate that they are essential for growth. ResB is predicted to be a transmembrane protein.
pfam04264, YceI, YceI-like domain. E. coli YceI is a base-induced periplasmic protein. The recent structure of a member of this family shows that it binds to poly-isoprenoid. The structure consists of an extended, eight-stranded, antiparallel beta-barrel that resembles the lipocalin fold.
pfam03861, ANTAR, ANTAR domain. ANTAR (AmiR and NasR transcription antitermination regulators) is an RNA-binding domain found in bacterial transcription antitermination regulatory proteins. The majority of the domain consists of a coiled-coil.
pfam00300, His_Phos_1, Histidine phosphatase superfamily (branch 1). The histidine phosphatase superfamily is so named because catalysis centers on a conserved His residue that is transiently phosphorylated during the catalytic cycle. Other conserved residues contribute to a 'phosphate pocket' and interact with the phospho group of substrate before, during and after its transfer to the His residue. Structure and sequence analyses show that different families contribute different additional residues to the 'phosphate pocket' and, more surprisingly, differ in the position, in sequence and in three dimensions, of a catalytically essential acidic residue. The superfamily may be divided into two main branches. The larger branch 1 contains a wide variety of catalytic functions, the best known being fructose 2,6-bisphosphatase (found in a bifunctional protein with 2-phosphofructokinase) and cofactor-dependent phosphoglycerate mutase. The latter is an unusual example of a mutase activity in the superfamily: the vast majority of members appear to be phosphatases. The bacterial regulatory protein phosphatase SixA is also in branch 1 and has a minimal, and possible ancestral-like structure, lacking the large domain insertions that contribute to binding of small molecules in branch 1 members.
TIGR01490, Uncharacterized_protein_Rv3661/MT3761, HAD-superfamily subfamily IB hydrolase, TIGR01490. This hypothetical equivalog is a member of the IB subfamily (TIGR01488) of the haloacid dehalogenase (HAD) superfamily of aspartate-nucleophile hydrolases. The sequences modelled here are all bacterial. The IB subfamily includes the enzyme phosphoserine phosphatase (TIGR00338). Due to this relationship, several of these sequences have been annotated as "phosphoserine phosphatase related proteins," or "Phosphoserine phosphatase-family enzymes." There is presently no evidence that any of the enzymes in this model possess PSPase activity. OMNI|NTL01ML1250 is annotated as a "possible transferase," however this is due to the C-terminal domain found on this sequence which is homologous to a group of glycerol-phosphate acyltransferases (between trusted and noise to TIGR00530). A subset of these sequences including OMNI|CC1962, the Caulobacter crescentus CicA protein cluster together and may represent a separate equivalog. [Unknown function, Enzymes of unknown specificity].
cd02966, TlpA_like_family, TlpA-like family; composed of TlpA, ResA, DsbE and similar proteins. TlpA, ResA and DsbE are bacterial protein disulfide reductases with important roles in cytochrome maturation. They are membrane-anchored proteins with a soluble TRX domain containing a CXXC motif located in the periplasm. The TRX domains of this family contain an insert, approximately 25 residues in length, which correspond to an extra alpha helix and a beta strand when compared with TRX. TlpA catalyzes an essential reaction in the biogenesis of cytochrome aa3, while ResA and DsbE are essential proteins in cytochrome c maturation. Also included in this family are proteins containing a TlpA-like TRX domain with domain architectures similar to E. coli DipZ protein, and the N-terminal TRX domain of PilB protein from Neisseria which acts as a disulfide reductase that can recylce methionine sulfoxide reductases.
TIGR01764, Probable_excisionase, DNA binding domain, excisionase family. An excisionase, or Xis protein, is a small protein that binds and promotes excisive recombination; it is not enzymatically active. This model represents a number of putative excisionases and related proteins from temperate phage, plasmids, and transposons, as well as DNA binding domains of other proteins, such as a DNA modification methylase. This model identifies mostly small proteins and N-terminal regions of large proteins, but some proteins appear to have two copies. This domain appears similar, in both sequence and predicted secondary structure (PSIPRED) to the MerR family of transcriptional regulators (pfam00376). [Unknown function, General].
pfam02683, DsbD, Cytochrome C biogenesis protein transmembrane region. This family consists of the transmembrane (i.e. non-catalytic) region of Cytochrome C biogenesis proteins also known as disulphide interchange proteins. These proteins posses a protein disulphide isomerase like domain that is not found within the aligned region of this family.
pfam09849, DUF2076, Uncharacterized protein conserved in bacteria (DUF2076). This domain, found in various hypothetical prokaryotic proteins, has no known function. The domain, however, is found in various periplasmic ligand-binding sensor proteins.
pfam03779, SPW, SPW repeat. A short repeat found in a small family of membrane-bound proteins. This repeat contains a conserved SPW motif in the first of two transmembrane helices.
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.
cd05328, 3alpha_HSD_SDR_c, alpha hydroxysteroid dehydrogenase (3alpha_HSD), classical (c) SDRs. Bacterial 3-alpha_HSD, which catalyzes the NAD-dependent oxidoreduction of hydroxysteroids, is a dimeric member of the classical SDR family. 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 15-hydroxyprostaglandin dehydrogenase (15-PGDH) numbering). 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) 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.
