cd00552, RaiA, RaiA ("ribosome-associated inhibitor A", also known as Protein Y (PY), YfiA, and SpotY, is a stress-response protein that binds the ribosomal subunit interface and arrests translation by interfering with aminoacyl-tRNA binding to the ribosomal A site. RaiA is also thought to counteract miscoding at the A site thus reducing translation errors. The RaiA fold structurally resembles the double-stranded RNA-binding domain (dsRBD).
TIGR04183, hypothetical_protein, Por secretion system C-terminal sorting domain. Species that include Porphyromonas gingivalis, Fibrobacter succinogenes, Flavobacterium johnsoniae, Cytophaga hutchinsonii, Gramella forsetii, Prevotella intermedia, and Salinibacter ruber average twenty or more copies of a C-terminal domain, represented by this model, associated with sorting to the outer membrane and covalent modification.
TIGR01730, COG0845:_Membrane-fusion_protein, RND family efflux transporter, MFP subunit. This model represents the MFP (membrane fusion protein) component of the RND family of transporters. RND refers to Resistance, Nodulation, and cell Division. It is, in part, a subfamily of pfam00529 (Pfam release 7.5) but hits substantial numbers of proteins missed by that model. The related HlyD secretion protein, for which pfam00529 is named, is outside the scope of this model. Attributed functions imply outward transport. These functions include nodulation, acriflavin resistance, heavy metal efflux, and multidrug resistance proteins. Most members of this family are found in Gram-negative bacteria. The proposed function of MFP proteins is to bring the inner and outer membranes together and enable transport to the outside of the outer membrane. Note, however, that a few members of this family are found in Gram-positive bacteria, where there is no outer membrane. [Transport and binding proteins, Unknown substrate].
cd10456, GIY-YIG_UPF0213, The GIY-YIG domain of uncharacterized protein family UPF0213 related to structure-specific endonuclease SLX1. This family contains a group of uncharacterized proteins found mainly in bacteria and several in dsDNA viruses. Although their function roles have not been recognized, these proteins show significant sequence similarities with the N-terminal GIY-YIG endonuclease domain of structure-specific endonuclease subunit SLX1, which binds another structure-specific endonuclease subunit SLX4 to form an active heterodimeric SLX1-SLX4 complex. This complex functions as a 5' flap endonuclease in yeast, and has also been identified as a Holliday junction resolvase in human.
pfam01292, Ni_hydr_CYTB, Prokaryotic cytochrome b561. This family includes cytochrome b561 and related proteins, in addition to the nickel-dependent hydrogenases b-type cytochrome subunit. Cytochrome b561 is a secretory vesicle-specific electron transport protein. It is an integral membrane protein, that binds two heme groups non-covalently. This is a prokaryotic family. Members of the 'eukaryotic cytochrome b561' family can be found in pfam03188.
pfam00582, Usp, Universal stress protein family. The universal stress protein UspA is a small cytoplasmic bacterial protein whose expression is enhanced when the cell is exposed to stress agents. UspA enhances the rate of cell survival during prolonged exposure to such conditions, and may provide a general "stress endurance" activity. The crystal structure of Haemophilus influenzae UspA reveals an alpha/beta fold similar to that of the Methanococcus jannaschii MJ0577 protein, which binds ATP, though UspA lacks ATP-binding activity.
cd14797, DUF302, Uncharacterized domain family DUF302. These domains are mostly found in bacterial single-domain proteins and have been shown to form homodimers; they may also bind zinc. Also characterized as COG3439.
cd17495, RMtype1_S_Cep9333ORF4827P-TRD2-CR2_like, Type I restriction-modification system specificity (S) subunit Target Recognition Domain-ConseRved domain (TRD-CR), similar to Crinalium epipsammum S subunit (S.Cep9333ORF4827P) TRD2-CR2 and Corynebacterium genitalium sp. nov. S subunit (S.CgeORF10704P) TRD2-CR2. The recognition sequences for Crinalium epipsammum S subunit (S.Cep9333ORF4827P) and Corynebacterium genitalium sp. nov. S subunit (S.CgeORF10704P) are undetermined. The restriction-modification (RM) system S subunit consists of two variable target recognition domains (TRD1 and 2) and two conserved regions (CR1 and CR2) which separate the TRDs. The TRDs each bind to different specific sequences in the DNA. RM systems protect a bacterial cell against invasion of foreign DNA by endonucleolytic cleavage of DNA that lacks a site specific modification. The host genome is protected from cleavage by methylation of specific nucleotides in the target sites. In type I systems, both restriction and modification activities are present in one enzyme complex composed of one DNA specificity (S) subunit (this family), two modification (M) subunits and two restriction (R) subunits. This model contains both TRD1-CR1 and TRD2-CR2. This subfamily of TRD-CR's shows similarity to TRD1-CR1 of Aminobacterium colombiense DSM 12261 S subunit (S.Aco12261I), which recognizes 5'... GCANNNNNNTGT ... 3'. This subfamily may also include TRD-CR-like sequence-recognition domains of various type II restriction enzymes and methyltransferases and type I DNA methyltransferases.
cd09176, PLDc_unchar6, Putative catalytic domain of uncharacterized hypothetical proteins with one or two copies of the HKD motif. Putative catalytic domain of uncharacterized hypothetical proteins with similarity to phospholipase D (PLD, EC 3.1.4.4). PLD enzymes hydrolyze phospholipid phosphodiester bonds to yield phosphatidic acid and a free polar head group. They can also catalyze transphosphatidylation of phospholipids to acceptor alcohols. Members of this subfamily contain one or two copies of the HKD motif (H-x-K-x(4)-D, where x represents any amino acid residue) that characterizes the PLD superfamily.
pfam07929, PRiA4_ORF3, Plasmid pRiA4b ORF-3-like protein. Members of this family are similar to the protein product of ORF-3 found on plasmid pRiA4 in the bacterium Agrobacterium rhizogenes. This plasmid is responsible for tumorigenesis at wound sites of plants infected by this bacterium, but the ORF-3 product does not seem to be involved in the pathogenetic process. Other proteins found in this family are annotated as being putative TnpR resolvases, but no further evidence was found to back this. Moreover, another member of this family is described as a probable lexA repressor and in fact carries a LexA DNA binding domain (pfam01726), but no references were found to expand on this.
pfam04932, Wzy_C, O-Antigen ligase. This group of bacterial proteins is involved in the synthesis of O-antigen, a lipopolysaccharide found in the outer membrane in gram-negative bacteria. This family includes O-antigen ligases such as E. coli RfaL.
pfam00902, TatC, Sec-independent protein translocase protein (TatC). The bacterial Tat system has a remarkable ability to transport folded proteins even enzyme complexes across the cytoplasmic membrane. It is structurally and mechanistically similar to the Delta pH-driven thylakoidal protein import pathway. A functional Tat system or Delta pH-dependent pathway requires three integral membrane proteins: TatA/Tha4, TatB/Hcf106 and TatC/cpTatC. The TatC protein is essential for the function of both pathways. It might be involved in twin-arginine signal peptide recognition, protein translocation and proton translocation. Sequence analysis predicts that TatC contains six transmembrane helices (TMHs), and experimental data confirmed that N- and C-termini of TatC or cpTatC are exposed to the cytoplasmic or stromal face of the membrane. The cytoplasmic N-terminus and the first cytoplasmic loop region of the Escherichia coli TatC protein are essential for protein export. At least two TatC molecules co-exist within each Tat translocon.
cd03801, GT4_PimA-like, phosphatidyl-myo-inositol mannosyltransferase. This family is most closely related to the GT4 family of glycosyltransferases and named after PimA in Propionibacterium freudenreichii, which is involved in the biosynthesis of phosphatidyl-myo-inositol mannosides (PIM) which are early precursors in the biosynthesis of lipomannans (LM) and lipoarabinomannans (LAM), and catalyzes the addition of a mannosyl residue from GDP-D-mannose (GDP-Man) to the position 2 of the carrier lipid phosphatidyl-myo-inositol (PI) to generate a phosphatidyl-myo-inositol bearing an alpha-1,2-linked mannose residue (PIM1). Glycosyltransferases catalyze the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. The acceptor molecule can be a lipid, a protein, a heterocyclic compound, or another carbohydrate residue. This group of glycosyltransferases is most closely related to the previously defined glycosyltransferase family 1 (GT1). The members of this family may transfer UDP, ADP, GDP, or CMP linked sugars. The diverse enzymatic activities among members of this family reflect a wide range of biological functions. The protein structure available for this family has the GTB topology, one of the two protein topologies observed for nucleotide-sugar-dependent glycosyltransferases. GTB proteins have distinct N- and C- terminal domains each containing a typical Rossmann fold. The two domains have high structural homology despite minimal sequence homology. The large cleft that separates the two domains includes the catalytic center and permits a high degree of flexibility. The members of this family are found mainly in certain bacteria and archaea.
TIGR03025, EPS_sugtrans, exopolysaccharide biosynthesis polyprenyl glycosylphosphotransferase. Members of this family are generally found near other genes involved in the biosynthesis of a variety of exopolysaccharides. These proteins consist of two fused domains, an N-terminal hydrophobic domain of generally low conservation and a highly conserved C-terminal sugar transferase domain (pfam02397). Characterized and partially characterized members of this subfamily include Salmonella WbaP (originally RfbP), E. coli WcaJ, Methylobacillus EpsB, Xanthomonas GumD, Vibrio CpsA, Erwinia AmsG, Group B Streptococcus CpsE (originally CpsD), and Streptococcus suis Cps2E. Each of these is believed to act in transferring the sugar from, for instance, UDP-glucose or UDP-galactose, to a lipid carrier such as undecaprenyl phosphate as the first (priming) step in the synthesis of an oligosaccharide "block". This function is encoded in the C-terminal domain. The liposaccharide is believed to be subsequently transferred through a "flippase" function from the cytoplasmic to the periplasmic face of the inner membrane by the N-terminal domain. Certain closely related transferase enzymes, such as Sinorhizobium ExoY and Lactococcus EpsD, lack the N-terminal domain and are not found by this model.
pfam03016, Exostosin, Exostosin family. The EXT family is a family of tumor suppressor genes. Mutations of EXT1 on 8q24.1, EXT2 on 11p11-13, and EXT3 on 19p have been associated with the autosomal dominant disorder known as hereditary multiple exostoses (HME). This is the most common known skeletal dysplasia. The chromosomal locations of other EXT genes suggest association with other forms of neoplasia. EXT1 and EXT2 have both been shown to encode a heparan sulphate polymerase with both D-glucuronyl (GlcA) and N-acetyl-D-glucosaminoglycan (GlcNAC) transferase activities. The nature of the defect in heparan sulphate biosynthesis in HME is unclear.
cd03801, GT4_PimA-like, phosphatidyl-myo-inositol mannosyltransferase. This family is most closely related to the GT4 family of glycosyltransferases and named after PimA in Propionibacterium freudenreichii, which is involved in the biosynthesis of phosphatidyl-myo-inositol mannosides (PIM) which are early precursors in the biosynthesis of lipomannans (LM) and lipoarabinomannans (LAM), and catalyzes the addition of a mannosyl residue from GDP-D-mannose (GDP-Man) to the position 2 of the carrier lipid phosphatidyl-myo-inositol (PI) to generate a phosphatidyl-myo-inositol bearing an alpha-1,2-linked mannose residue (PIM1). Glycosyltransferases catalyze the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. The acceptor molecule can be a lipid, a protein, a heterocyclic compound, or another carbohydrate residue. This group of glycosyltransferases is most closely related to the previously defined glycosyltransferase family 1 (GT1). The members of this family may transfer UDP, ADP, GDP, or CMP linked sugars. The diverse enzymatic activities among members of this family reflect a wide range of biological functions. The protein structure available for this family has the GTB topology, one of the two protein topologies observed for nucleotide-sugar-dependent glycosyltransferases. GTB proteins have distinct N- and C- terminal domains each containing a typical Rossmann fold. The two domains have high structural homology despite minimal sequence homology. The large cleft that separates the two domains includes the catalytic center and permits a high degree of flexibility. The members of this family are found mainly in certain bacteria and archaea.
cd00761, Glyco_tranf_GTA_type, Glycosyltransferase family A (GT-A) includes diverse families of glycosyl transferases with a common GT-A type structural fold. Glycosyltransferases (GTs) are enzymes that synthesize oligosaccharides, polysaccharides, and glycoconjugates by transferring the sugar moiety from an activated nucleotide-sugar donor to an acceptor molecule, which may be a growing oligosaccharide, a lipid, or a protein. Based on the stereochemistry of the donor and acceptor molecules, GTs are classified as either retaining or inverting enzymes. To date, all GT structures adopt one of two possible folds, termed GT-A fold and GT-B fold. This hierarchy includes diverse families of glycosyl transferases with a common GT-A type structural fold, which has two tightly associated beta/alpha/beta domains that tend to form a continuous central sheet of at least eight beta-strands. The majority of the proteins in this superfamily are Glycosyltransferase family 2 (GT-2) proteins. But it also includes families GT-43, GT-6, GT-8, GT13 and GT-7; which are evolutionarily related to GT-2 and share structure similarities.
pfam13387, DUF4105, Domain of unknown function (DUF4105). This is a family of uncharacterized bacterial proteins. There is a highly conserved histidine residue and a well-conserved NCT motif.
cd03801, GT4_PimA-like, phosphatidyl-myo-inositol mannosyltransferase. This family is most closely related to the GT4 family of glycosyltransferases and named after PimA in Propionibacterium freudenreichii, which is involved in the biosynthesis of phosphatidyl-myo-inositol mannosides (PIM) which are early precursors in the biosynthesis of lipomannans (LM) and lipoarabinomannans (LAM), and catalyzes the addition of a mannosyl residue from GDP-D-mannose (GDP-Man) to the position 2 of the carrier lipid phosphatidyl-myo-inositol (PI) to generate a phosphatidyl-myo-inositol bearing an alpha-1,2-linked mannose residue (PIM1). Glycosyltransferases catalyze the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. The acceptor molecule can be a lipid, a protein, a heterocyclic compound, or another carbohydrate residue. This group of glycosyltransferases is most closely related to the previously defined glycosyltransferase family 1 (GT1). The members of this family may transfer UDP, ADP, GDP, or CMP linked sugars. The diverse enzymatic activities among members of this family reflect a wide range of biological functions. The protein structure available for this family has the GTB topology, one of the two protein topologies observed for nucleotide-sugar-dependent glycosyltransferases. GTB proteins have distinct N- and C- terminal domains each containing a typical Rossmann fold. The two domains have high structural homology despite minimal sequence homology. The large cleft that separates the two domains includes the catalytic center and permits a high degree of flexibility. The members of this family are found mainly in certain bacteria and archaea.
pfam01636, APH, Phosphotransferase enzyme family. This family consists of bacterial antibiotic resistance proteins, which confer resistance to various aminoglycosides they include: aminoglycoside 3'-phosphotransferase or kanamycin kinase / neomycin-kanamycin phosphotransferase and streptomycin 3''-kinase or streptomycin 3''-phosphotransferase. The aminoglycoside phosphotransferases inactivate aminoglycoside antibiotics via phosphorylation. This family also includes homoserine kinase. This family is related to fructosamine kinase pfam03881.
pfam00534, Glycos_transf_1, Glycosyl transferases group 1. Mutations in this domain of PIGA lead to disease (Paroxysmal Nocturnal haemoglobinuria). Members of this family transfer activated sugars to a variety of substrates, including glycogen, Fructose-6-phosphate and lipopolysaccharides. Members of this family transfer UDP, ADP, GDP or CMP linked sugars. The eukaryotic glycogen synthases may be distant members of this family.
cd03218, ABC_YhbG, ATP-binding cassette component of YhbG transport system. The ABC transporters belonging to the YhbG family are similar to members of the Mj1267_LivG family, which is involved in the transport of branched-chain amino acids. The genes yhbG and yhbN are located in a single operon and may function together in cell envelope during biogenesis. YhbG is the putative ATP-binding cassette component and YhbN is the putative periplasmic-binding protein. Depletion of each gene product leads to growth arrest, irreversible cell damage and loss of viability in E. coli. The YhbG homolog (NtrA) is essential in Rhizobium meliloti, a symbiotic nitrogen-fixing bacterium.
pfam04231, Endonuclease_1, Endonuclease I. Bacterial periplasmic or secreted endonuclease I (EC:3.1.21.1) E. coli endonuclease I (EndoI) is a sequence independent endonuclease located in the periplasm. It is inhibited by different RNA species. It is thought to normally generate double strand breaks in DNA, except in the presence of high salt concentrations and RNA, when it generates single strand breaks in DNA. Its biological role is unknown. Other family members are known to be extracellular. This family also includes a non-specific, Mg2+ activated ribonuclease precursor.
TIGR01579, MiaB-like-C, MiaB-like tRNA modifying enzyme. This clade of sequences is closely related to MiaB, a modifier of isopentenylated adenosine-37 of certain eukaryotic and bacterial tRNAs (see TIGR01574). Sequence alignments suggest that this equivalog performs the same chemical transformation as MiaB, perhaps on a different (or differently modified) tRNA base substrate. This clade is a member of a subfamily (TIGR00089) and spans low GC Gram positive bacteria, alpha and epsilon proteobacteria, Campylobacter, Porphyromonas, Aquifex, Thermotoga, Chlamydia, Treponema and Fusobacterium. [Protein synthesis, tRNA and rRNA base modification].
cd16894, MltD-like, Membrane-bound lytic murein transglycosylase D and similar proteins. Lytic transglycosylases (LT) catalyze the cleavage of the beta-1,4-glycosidic bond between N-acetylmuramic acid (MurNAc) and N-acetyl-D-glucosamine (GlcNAc). Membrane-bound lytic murein transglycosylase D protein (MltD) family members may have one or more small LysM domains, which may contribute to peptidoglycan binding. Unlike the similar "goose-type" lysozymes, LTs also make a new glycosidic bond with the C6 hydroxyl group of the same muramic acid residue. Proteins similar to this family include the soluble and insoluble membrane-bound LTs in bacteria, the LTs in bacteriophage lambda, as well as the eukaryotic "goose-type" lysozymes (goose egg-white lysozyme; GEWL).
pfam14542, Acetyltransf_CG, GCN5-related N-acetyl-transferase. This family of GCN5-related N-acetyl-transferases bind both CoA and acetyl-CoA. They are characterized by highly conserved glycine, a cysteine residue in the acetyl-CoA binding site near the acetyl group, their small size compared with other GNATs and a lack of of an obvious substrate-binding site. It is proposed that they transfer an acetyl group from acetyl-CoA to one or more unidentified aliphatic amines via an acetyl (cysteine) enzyme intermediate. The substrate might be another macromolecule.
cd04179, DPM_DPG-synthase_like, DPM_DPG-synthase_like is a member of the Glycosyltransferase 2 superfamily. DPM1 is the catalytic subunit of eukaryotic dolichol-phosphate mannose (DPM) synthase. DPM synthase is required for synthesis of the glycosylphosphatidylinositol (GPI) anchor, N-glycan precursor, protein O-mannose, and C-mannose. In higher eukaryotes,the enzyme has three subunits, DPM1, DPM2 and DPM3. DPM is synthesized from dolichol phosphate and GDP-Man on the cytosolic surface of the ER membrane by DPM synthase and then is flipped onto the luminal side and used as a donor substrate. In lower eukaryotes, such as Saccharomyces cerevisiae and Trypanosoma brucei, DPM synthase consists of a single component (Dpm1p and TbDpm1, respectively) that possesses one predicted transmembrane region near the C terminus for anchoring to the ER membrane. In contrast, the Dpm1 homologues of higher eukaryotes, namely fission yeast, fungi, and animals, have no transmembrane region, suggesting the existence of adapter molecules for membrane anchoring. This family also includes bacteria and archaea DPM1_like enzymes. However, the enzyme structure and mechanism of function are not well understood. The UDP-glucose:dolichyl-phosphate glucosyltransferase (DPG_synthase) is a transmembrane-bound enzyme of the endoplasmic reticulum involved in protein N-linked glycosylation. This enzyme catalyzes the transfer of glucose from UDP-glucose to dolichyl phosphate. This protein family belongs to Glycosyltransferase 2 superfamily.
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.
