pfam13614, AAA_31, AAA domain. This family includes a wide variety of AAA domains including some that have lost essential nucleotide binding residues in the P-loop.
pfam00583, Acetyltransf_1, Acetyltransferase (GNAT) family. This family contains proteins with N-acetyltransferase functions such as Elp3-related proteins.
cd03424, ADPRase_NUDT5, ADP-ribose pyrophosphatase (ADPRase) catalyzes the hydrolysis of ADP-ribose and a variety of additional ADP-sugar conjugates to AMP and ribose-5-phosphate. Like other members of the Nudix hydrolase superfamily, it requires a divalent cation, such as Mg2+, for its activity. It also contains a highly conserved 23-residue Nudix motif (GX5EX7REUXEEXGU, where U = I, L or V) which functions as a metal binding site/catalytic site. In addition to the Nudix motif, there are additional conserved amino acid residues, distal from the signature sequence, that correlate with substrate specificity. In humans, there are four distinct ADPRase activities, three putative cytosolic enzymes (ADPRase-I, -II, and -Mn) and a single mitochondrial enzyme (ADPRase-m). Human ADPRase-II is also referred to as NUDT5. It lacks the N-terminal target sequence unique to mitochondrial ADPRase. The different cytosolic types are distinguished by their specificities for substrate and specific requirement for metal ions. NUDT5 forms a homodimer.
COG1188, COG1188, Ribosome-associated heat shock protein implicated in the recycling of the 50S subunit (S4 paralog) [Translation, ribosomal structure and biogenesis].
cd02883, Nudix_Hydrolase, Nudix hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes 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. Members of this family are recognized by a highly conserved 23-residue nudix motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of nudix hydrolase 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 and "house-cleaning" enzymes. Substrate specificity is used to define child 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. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.
cd07530, HAD_Pase_UmpH-like, UmpH/NagD family phosphatase, similar to Escherichia coli UmpH UMP phosphatase/NagD nucleotide phosphatase and Mycobacterium tuberculosis Rv1692 glycerol 3-phosphate phosphatase. Escherichia coli UmpH/NagD is a ribonucleoside tri-, di-, and monophosphatase with a preference for purines, it shows peak activity with UMP and functions in UMP-degradation. It is also an effective phosphatase with AMP, GMP and CMP. Mycobacterium tuberculosis phosphatase, Rv1692 is a glycerol 3-phosphate phosphatase. Rv1692 is the final enzyme involved in glycerophospholipid recycling/catabolism. This subfamily belongs to the UmpH/NagD phosphatase family, and to the haloacid dehalogenase-like (HAD) hydrolases, a large superfamily of diverse enzymes that catalyze carbon or phosphoryl group transfer reactions on a range of substrates, using an active site aspartate in nucleophilic catalysis. Members of this superfamily include 2-L-haloalkanoic acid dehalogenase, azetidine hydrolase, phosphonoacetaldehyde hydrolase, phosphoserine phosphatase, phosphomannomutase, P-type ATPases and many others. HAD hydrolases are found in all three kingdoms of life, and most genomes are predicted to contain multiple HAD-like proteins. Members possess a highly conserved alpha/beta core domain, and many also possess a small cap domain, the fold and function of which is variable. HAD hydrolases are sometimes referred to as belonging to the DDDD superfamily of phosphohydrolases.
pfam07947, YhhN, YhhN family. The members of this family are similar to the hypothetical protein yhhN expressed by E. coli. Many are annotated as possible transmembrane proteins, and in fact they all have a high proportion of hydrophobic residues. A human member of this family, formerly known as TMEM86B, is a lysoplasmalogenase that catalyzes the hydrolysis of the vinyl ether bond of lysoplasmalogen. Putative conserved active site residues have been proposed for the YhhN family.
pfam13275, S4_2, S4 domain. The S4 domain is a small domain consisting of 60-65 amino acid residues that was detected in the bacterial ribosomal protein S4.
cd08512, PBP2_NikA_DppA_OppA_like_7, The substrate-binding component of an uncharacterized ABC-type nickel/dipeptide/oligopeptide-like import system contains the type 2 periplasmic binding fold. This CD represents the substrate-binding domain of an uncharacterized ATP-binding cassette (ABC) type nickel/dipeptide/oligopeptide-like transporter. The oligopeptide-binding protein OppA and the dipeptide-binding protein DppA show significant sequence similarity to NikA, the initial nickel receptor. The DppA binds dipeptides and some tripeptides and is involved in chemotaxis toward dipeptides, whereas the OppA binds peptides of a wide range of lengths (2-35 amino acid residues) and plays a role in recycling of cell wall peptides, which precludes any involvement in chemotaxis. Most of other periplasmic binding proteins are comprised of only two globular subdomains corresponding to domains I and III of the dipeptide/oligopeptide binding proteins. The structural topology of these domains is most similar to that of the type 2 periplasmic binding proteins (PBP2), which are responsible for the uptake of a variety of substrates such as phosphate, sulfate, polysaccharides, lysine/arginine/ornithine, and histidine. The PBP2 bind their ligand in the cleft between these domains in a manner resembling a Venus flytrap. After binding their specific ligand with high affinity, they can interact with a cognate membrane transport complex comprised of two integral membrane domains and two cytoplasmically located ATPase domains. This interaction triggers the ligand translocation across the cytoplasmic membrane energized by ATP hydrolysis. Besides transport proteins, the PBP2 superfamily includes the ligand-binding domains from ionotropic glutamate receptors, LysR-type transcriptional regulators, and unorthodox sensor proteins involved in signal transduction.
COG0444, DppD, ABC-type dipeptide/oligopeptide/nickel transport system, ATPase component [Amino acid transport and metabolism / Inorganic ion transport and metabolism].
pfam01872, RibD_C, RibD C-terminal domain. The function of this domain is not known, but it is thought to be involved in riboflavin biosynthesis. This domain is found in the C-terminus of RibD/RibG, in combination with pfam00383, as well as in isolation in some archaebacterial proteins. This family appears to be related to pfam00186.
COG0601, DppB, ABC-type dipeptide/oligopeptide/nickel transport systems, permease components [Amino acid transport and metabolism / Inorganic ion transport and metabolism].
cd05355, SDR_c1, classical (c) SDR, subgroup 1. These proteins are members of the classical SDR family, with a canonical active site tetrad and a typical Gly-rich NAD-binding motif. 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.
TIGR00665, DnaB, replicative DNA helicase. This model describes the helicase DnaB, a homohexameric protein required for DNA replication. The homohexamer can form a ring around a single strand of DNA near a replication fork. An intein of > 400 residues is found at a conserved location in DnaB of Synechocystis PCC6803, Rhodothermus marinus (both experimentally confirmed), and Mycobacterium tuberculosis. The intein removes itself by a self-splicing reaction. The seed alignment contains inteins so that the model built from the seed alignment will model a low cost at common intein insertion sites. [DNA metabolism, DNA replication, recombination, and repair].
COG1173, DppC, ABC-type dipeptide/oligopeptide/nickel transport systems, permease components [Amino acid transport and metabolism / Inorganic ion transport and metabolism].
TIGR02957, putative_sigma_factor, RNA polymerase sigma-70 factor, TIGR02957 family. This group of sigma factors are members of the sigma-70 family (TIGR02937). They and appear by homology, tree building and bidirectional best hits, to represent a conserved family. This family is found in a limited number of bacterial lineages. This family includes apparent paralogous expansion in Streptomyces coelicolor A3(2), and multiple copies in Mycobacterium smegmatis MC2, Streptomyces avermitilis MA-4680 and Nocardia farcinica IFM10152.
