cd03873, Zinc_peptidase_like, Zinc peptidases M18, M20, M28, and M42. Zinc peptidases play vital roles in metabolic and signaling pathways throughout all kingdoms of life. This hierarchy contains zinc peptidases that correspond to the MH clan in the MEROPS database, which contains 4 families (M18, M20, M28, M42). The peptidase M20 family includes carboxypeptidases such as the glutamate carboxypeptidase from Pseudomonas, the thermostable carboxypeptidase Ss1 of broad specificity from archaea and yeast Gly-X carboxypeptidase. The dipeptidases include bacterial dipeptidase, peptidase V (PepV), a non-specific eukaryotic dipeptidase, and two Xaa-His dipeptidases (carnosinases). There is also the bacterial aminopeptidase, peptidase T (PepT) that acts only on tripeptide substrates and has therefore been termed a tripeptidase. Peptidase family M28 contains aminopeptidases and carboxypeptidases, and has co-catalytic zinc ions. However, several enzymes in this family utilize other first row transition metal ions such as cobalt and manganese. Each zinc ion is tetrahedrally co-ordinated, with three amino acid ligands plus activated water; one aspartate residue binds both metal ions. The aminopeptidases in this family are also called bacterial leucyl aminopeptidases, but are able to release a variety of N-terminal amino acids. IAP aminopeptidase and aminopeptidase Y preferentially release basic amino acids while glutamate carboxypeptidase II preferentially releases C-terminal glutamates. Glutamate carboxypeptidase II and plasma glutamate carboxypeptidase hydrolyze dipeptides. Peptidase families M18 and M42 contain metallo-aminopeptidases. M18 is widely distributed in bacteria and eukaryotes. However, only yeast aminopeptidase I and mammalian aspartyl aminopeptidase have been characterized in detail. Some M42 (also known as glutamyl aminopeptidase) enzymes exhibit aminopeptidase specificity while others also have acylaminoacyl-peptidase activity (i.e. hydrolysis of acylated N-terminal residues).
cd01992, PP-ATPase, N-terminal domain of predicted ATPase of the PP-loop faimly implicated in cell cycle control [Cell division and chromosome partitioning]. This is a subfamily of Adenine nucleotide alpha hydrolases superfamily.Adeninosine nucleotide alpha hydrolases superfamily includes N type ATP PPases and ATP sulphurylases. It forms a apha/beta/apha fold which binds to Adenosine group. This domain has a strongly conserved motif SGGXD at the N terminus.
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].
cd12822, TmCorA-like, Thermotoga maritima CorA-like family. This family belongs to the MIT superfamily of essential membrane proteins involved in transporting divalent cations (uptake or efflux) across membranes. Members of the Thermotoga maritima CorA_like family are found in all three kingdoms of life. It is a functionally diverse family, in addition to the CorA Co2+ transporter from the hyperthermophilic Thermotoga maritima, it includes three Saccharomyces cerevisiae members: two plasma membrane proteins, the Mg2+ transporter Alr1p/Swc3p and the putative Mg2+ transporter, Alr2p, and the vacuole membrane protein Mnr2p, a putative Mg2+ transporter. Thermotoga maritima CorA forms funnel-shaped homopentamers, the tip of the funnel is formed from two C-terminal transmembrane (TM) helices from each monomer, and the large opening of the funnel from the N-terminal cytoplasmic domains. The GMN signature motif of the MIT superfamily occurs just after TM1, mutation within this motif is known to abolish Mg2+ transport by Alr1p. Natural variants in this signature sequence may be associated with the transport of different divalent cations. The functional diversity of the MIT superfamily may also be due to minor structural differences regulating gating, substrate selection, and transport.
cd06251, M14_ASTE_ASPA-like, Peptidase M14 Succinylglutamate desuccinylase (ASTE)/aspartoacylase (ASPA)-like; uncharacterized subgroup. A functionally uncharacterized subgroup of the Succinylglutamate desuccinylase (ASTE)/aspartoacylase (ASPA) subfamily which is part of the M14 family of metallocarboxypeptidases. ASTE catalyzes the fifth and last step in arginine catabolism by the arginine succinyltransferase pathway, and aspartoacylase (ASPA, also known as aminoacylase 2, and ACY-2; EC:3.5.1.15) cleaves N-acetyl L-aspartic acid (NAA) into aspartate and acetate. NAA is abundant in the brain, and hydrolysis of NAA by ASPA may help maintain white matter. ASPA is an NAA scavenger in other tissues. Mutations in the gene encoding ASPA cause Canavan disease (CD), a fatal progressive neurodegenerative disorder involving dysmyelination and spongiform degeneration of white matter in children. This enzyme binds zinc which is necessary for activity. Measurement of elevated NAA levels in urine is used in the diagnosis of CD.
pfam14899, DUF4492, Domain of unknown function (DUF4492). This family of proteins is found in bacteria. Proteins in this family are approximately 80 amino acids in length. The function of these proteins is unknown.
cd01347, ligand_gated_channel, TonB dependent/Ligand-Gated channels are created by a monomeric 22 strand (22,24) anti-parallel beta-barrel. Ligands apparently bind to the large extracellular loops. The N-terminal 150-200 residues form a plug from the periplasmic end of barrel. Energy (proton-motive force) and TonB-dependent conformational alteration of channel (parts of plug, and loops 7 and 8) allow passage of ligand. FepA residues 12-18 form the TonB box, which mediates the interaction with the TonB-containing inner membrane complex. TonB preferentially interacts with ligand-bound receptors. Transport thru the channel may resemble passage thru an air lock. In this model, ligand binding leads to closure of the extracellular end of pore, then a TonB-mediated signal facillitates opening of the interior side of pore, deforming the N-terminal plug and allowing passage of the ligand to the periplasm. Such a mechanism would prevent the free diffusion of small molecules thru the pore.
pfam02322, Cyt_bd_oxida_II, Cytochrome bd terminal oxidase subunit II. This family consists of cytochrome bd type terminal oxidases that catalyze quinol-dependent, Na+-independent oxygen uptake. Members of this family are integral membrane proteins and contain a protohaem IX centre B558. One member of the family, Klebsiella pneumoniae CydB, is implicated in having an important role in micro-aerobic nitrogen fixation in the enteric bacterium Klebsiella pneumoniae. The family forms an integral functional unit with subunit I, family Bac_Ubq_Cox, pfam01654.
pfam01654, Cyt_bd_oxida_I, Cytochrome bd terminal oxidase subunit I. This family are the alternative oxidases found in many bacteria which oxidize ubiquinol and reduce oxygen as part of the electron transport chain. This family is the subunit I of the oxidase E. coli has two copies of the oxidase, bo and bd', both of which are represented here In some nitrogen fixing bacteria, e.g. Klebsiella pneumoniae this oxidase is responsible for removing oxygen in microaerobic conditions, making the oxidase required for nitrogen fixation. This subunit binds a single b-haem, through ligands at His186 and Met393 (using SW:P11026 numbering). In addition His19 is a ligand for the haem b found in subunit II.
TIGR02805, Biopolymer_transport_protein_ExbB, tonB-system energizer ExbB, group 2. Members of this protein family appear to be the ExbB protein of an ExbBD proton-transporting membrane complex that, by means of TonB, energizes transport by TonB-dependent receptors. Note that this family represents one of at least two distinct groups TolQ homologs designated ExbB - see also TIGR02797. Each group associates with a distinct group of ExbD proteins, and a single species may have two ExbB/ExbD/TonB systems. [Transport and binding proteins, Cations and iron carrying compounds].
pfam02452, PemK_toxin, PemK-like, MazF-like toxin of type II toxin-antitoxin system. PemK is a growth inhibitor in E. coli known to bind to the promoter region of the Pem operon, auto-regulating synthesis. This family represents the toxin molecule of a typical bacterial toxin-antitoxin system pairing. The family includes a number of different toxins, such as MazF, Kid, PemK, ChpA, ChpB and ChpAK.
cd00756, MoaE, MoaE family. Members of this family are involved in biosynthesis of the molybdenum cofactor (Moco), an essential cofactor for a diverse group of redox enzymes. Moco biosynthesis is an evolutionarily conserved pathway present in eubacteria, archaea and eukaryotes. Moco contains a tricyclic pyranopterin, termed molybdopterin (MPT), which carries the cis-dithiolene group responsible for molybdenum ligation. This dithiolene group is generated by MPT synthase in the second major step in Moco biosynthesis. MPT synthase is a heterotetramer consisting of two large (MoaE) and two small (MoaD) subunits.
pfam08843, AbiEii, Nucleotidyl transferase AbiEii toxin, Type IV TA system. This family was recently identified as belonging to the nucleotidyltransferase superfamily. AbiEii is the cognate toxin of the type IV toxin-antitoxin 'innate immunity' bacterial abortive infection (Abi) system that protects bacteria from the spread of a phage infection. The Abi system is activated upon infection with phage to abort the cell thus preventing the spread of phage through viral replication. There are some 20 or more Abis, and they are predominantly plasmid-encoded lactococcal systems. TA, toxin-antitoxin, systems on plasmids function by killing cells that lose the plasmid upon division. AbiE phage resistance systems function as novel Type IV TAs and are widespread in bacteria and archaea. The cognate antitoxin is pfam13338.
cd07182, RNase_HII_bacteria_HII_like, Bacterial Ribonuclease HII-like. This family includes mostly bacterial type 2 RNases H, with some eukaryotic members. Bacterial RNase HII has a role in primer removal based on its involvement in ribonucleotide-specific catalytic activity in the presence of RNA/DNA hybrid substrates. Several bacteria, such as Bacillus subtilis, have two different type II RNases H, RNases HII and HIII; double deletion of these leads to cellular lethality. It appears that type I and type II RNases H also have overlapping functions in cells, as over-expression of Escherichia coli RNase HII can complement an RNase HI deletion phenotype. In Leishmania mitochondria, of the four distinct RNase H genes (H1, HIIA, HIIB, HIIC), HIIC is essential for the survival of the parasite and thus can be a potential target for anti-leishmanial chemotherapy. Ribonuclease H (RNase H) is classified into two families, type I (prokaryotic RNase HI, eukaryotic RNase H1 and viral RNase H) and type II (prokaryotic RNase HII and HIII, and eukaryotic RNase H2). RNase H endonucleolytically hydrolyzes an RNA strand when it is annealed to a complementary DNA strand in the presence of divalent cations, in DNA replication and repair.
cd00887, MoeA, MoeA family. Members of this family are involved in biosynthesis of the molybdenum cofactor (MoCF), an essential cofactor of a diverse group of redox enzymes. MoCF biosynthesis is an evolutionarily conserved pathway present in eubacteria, archaea and eukaryotes. MoCF contains a tricyclic pyranopterin, termed molybdopterin (MPT). MoeA, together with MoaB, is responsible for the metal incorporation into MPT, the third step in MoCF biosynthesis. The plant homolog Cnx1 is a MoeA-MogA fusion protein. The mammalian homolog gephyrin is a MogA-MoeA fusion protein, that plays a critical role in postsynaptic anchoring of inhibitory glycine receptors and major GABAa receptor subtypes.
cd00754, Ubl_MoaD, ubiquitin-like (Ubl) domain found in molybdenum cofactor biosynthesis protein D (MoaD) and similar proteins. MoaD, also termed molybdopterin synthase sulfur carrier subunit, or MPT synthase subunit 1, or MPT synthase small subunit, or molybdopterin-converting factor small subunit, or molybdopterin-converting factor subunit 1, is a conserved small sulfur carrier protein that has beta-grasp ubiquitin-like (Ubl) fold involved in biosynthesis of the molybdenum cofactor (Moco), an essential cofactor of a diverse group of redox enzymes. MoaD is activated in an ATP-dependent manner by sulfurtransferases similar to the activation mechanism of ubiquitin-activating enzyme E1.
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.
pfam02452, PemK_toxin, PemK-like, MazF-like toxin of type II toxin-antitoxin system. PemK is a growth inhibitor in E. coli known to bind to the promoter region of the Pem operon, auto-regulating synthesis. This family represents the toxin molecule of a typical bacterial toxin-antitoxin system pairing. The family includes a number of different toxins, such as MazF, Kid, PemK, ChpA, ChpB and ChpAK.
pfam02452, PemK_toxin, PemK-like, MazF-like toxin of type II toxin-antitoxin system. PemK is a growth inhibitor in E. coli known to bind to the promoter region of the Pem operon, auto-regulating synthesis. This family represents the toxin molecule of a typical bacterial toxin-antitoxin system pairing. The family includes a number of different toxins, such as MazF, Kid, PemK, ChpA, ChpB and ChpAK.
pfam08843, AbiEii, Nucleotidyl transferase AbiEii toxin, Type IV TA system. This family was recently identified as belonging to the nucleotidyltransferase superfamily. AbiEii is the cognate toxin of the type IV toxin-antitoxin 'innate immunity' bacterial abortive infection (Abi) system that protects bacteria from the spread of a phage infection. The Abi system is activated upon infection with phage to abort the cell thus preventing the spread of phage through viral replication. There are some 20 or more Abis, and they are predominantly plasmid-encoded lactococcal systems. TA, toxin-antitoxin, systems on plasmids function by killing cells that lose the plasmid upon division. AbiE phage resistance systems function as novel Type IV TAs and are widespread in bacteria and archaea. The cognate antitoxin is pfam13338.
cd00756, MoaE, MoaE family. Members of this family are involved in biosynthesis of the molybdenum cofactor (Moco), an essential cofactor for a diverse group of redox enzymes. Moco biosynthesis is an evolutionarily conserved pathway present in eubacteria, archaea and eukaryotes. Moco contains a tricyclic pyranopterin, termed molybdopterin (MPT), which carries the cis-dithiolene group responsible for molybdenum ligation. This dithiolene group is generated by MPT synthase in the second major step in Moco biosynthesis. MPT synthase is a heterotetramer consisting of two large (MoaE) and two small (MoaD) subunits.
pfam01755, Glyco_transf_25, Glycosyltransferase family 25 (LPS biosynthesis protein). Members of this family belong to Glycosyltransferase family 25 This is a family of glycosyltransferases involved in lipopolysaccharide (LPS) biosynthesis. These enzymes catalyze the transfer of various sugars onto the growing LPS chain during its biosynthesis.
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.
cd06433, GT_2_WfgS_like, WfgS and WfeV are involved in O-antigen biosynthesis. Escherichia coli WfgS and Shigella dysenteriae WfeV are glycosyltransferase 2 family enzymes involved in O-antigen biosynthesis. GT-2 enzymes have 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. These are enzymes that catalyze the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. Glycosyltransferases have been classified into more than 90 distinct sequence based families.
pfam02452, PemK_toxin, PemK-like, MazF-like toxin of type II toxin-antitoxin system. PemK is a growth inhibitor in E. coli known to bind to the promoter region of the Pem operon, auto-regulating synthesis. This family represents the toxin molecule of a typical bacterial toxin-antitoxin system pairing. The family includes a number of different toxins, such as MazF, Kid, PemK, ChpA, ChpB and ChpAK.
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.
pfam14897, EpsG, EpsG family. This family of proteins are related to the EpsG protein from B. subtilis. These proteins are likely glycosyl transferases belonging to the membrane protein GT-C clan.
cd00754, Ubl_MoaD, ubiquitin-like (Ubl) domain found in molybdenum cofactor biosynthesis protein D (MoaD) and similar proteins. MoaD, also termed molybdopterin synthase sulfur carrier subunit, or MPT synthase subunit 1, or MPT synthase small subunit, or molybdopterin-converting factor small subunit, or molybdopterin-converting factor subunit 1, is a conserved small sulfur carrier protein that has beta-grasp ubiquitin-like (Ubl) fold involved in biosynthesis of the molybdenum cofactor (Moco), an essential cofactor of a diverse group of redox enzymes. MoaD is activated in an ATP-dependent manner by sulfurtransferases similar to the activation mechanism of ubiquitin-activating enzyme E1.
cd02514, GT13_GLCNAC-TI, GT13_GLCNAC-TI is involved in an essential step in the synthesis of complex or hybrid-type N-linked oligosaccharides. Alpha-1,3-mannosyl-glycoprotein beta-1,2-N-acetylglucosaminyltransferase (GLCNAC-T I , GNT-I) transfers N-acetyl-D-glucosamine from UDP to high-mannose glycoprotein N-oligosaccharide, an essential step in the synthesis of complex or hybrid-type N-linked oligosaccharides. The enzyme is an integral membrane protein localized to the Golgi apparatus. The catalytic domain is located at the C-terminus. These proteins are members of the glycosy transferase family 13.
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')
