cd02215, cupin_QDO_N_C, quercetinase, N- and C-terminal cupin domains. This family contains quercetinase (also known as quercetin 2,3-dioxygenase, 2,3QD, QDO and YxaG; EC 1.13.11.24), a mononuclear copper-dependent dioxygenase that catalyzes the cleavage of the flavonol quercetin (5,7,3',4'-tetrahydroxyflavonol) heterocyclic ring to produce 2-protocatechuoyl-phloroglucinol carboxylic acid and carbon monoxide. Bacillus subtilis quercetin 2,3-dioxygenase (QDO) is a homodimer that shows oxygenase activity with several divalent metals such as Mn2+, Co2+, Fe2+, and Cu2+, although the preferred one appears to be Mn2+. The dioxygen binds to the metal ion of the Cu-QDO-quercetin complex, yielding a Cu2+-superoxo quercetin radical intermediate, which then forms a Cu2+-alkylperoxo complex which then evolves into endoperoxide intermediate that decomposes to the product. Quercetinase is a bicupin with two tandem cupin beta-barrel domains, both of which are included in this alignment model. The pirins, which also belong to the cupin domain family, have been shown to catalyze a reaction involving quercetin and may have a function similar to that of quercetinase.
cd03146, GAT1_Peptidase_E, Type 1 glutamine amidotransferase (GATase1)-like domain found in peptidase E. Type 1 glutamine amidotransferase (GATase1)-like domain found in peptidase E. This group contains proteins similar to the aspartyl dipeptidases Salmonella typhimurium peptidase E and Xenopus laevis peptidase E. In bacteria peptidase E is believed to play a role in degrading peptides generated by intracellular protein breakdown or imported into the cell as nutrient sources. Peptidase E uniquely hydrolyses only Asp-X dipeptides (where X is any amino acid), and one tripeptide Asp-Gly-Gly. Peptidase E is believed to be a serine peptidase having a Ser-His-Glu catalytic triad which differs from the Cys-His-Glu catalytic triad typical of GATase1 domains by having a Ser in place of the reactive Cys at the nucleophile elbow. Xenopus PepE is developmentally regulated in response to thyroid hormone and, it is thought to play a role in apoptosis during tail reabsorption.
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.
cd08252, AL_MDR, Arginate lyase and other MDR family members. This group contains a structure identified as an arginate lyase. Other members are identified quinone reductases, alginate lyases, and other proteins related to the zinc-dependent dehydrogenases/reductases. QOR catalyzes the conversion of a quinone and NAD(P)H to a hydroquinone and NAD(P+. Quinones are cyclic diones derived from aromatic compounds. Membrane bound QOR acts in the respiratory chains of bacteria and mitochondria, while soluble QOR acts to protect from toxic quinones (e.g. DT-diaphorase) or as a soluble eye-lens protein in some vertebrates (e.g. zeta-crystalin). QOR reduces quinones through a semi-quinone intermediate via a NAD(P)H-dependent single electron transfer. QOR is a member of the medium chain dehydrogenase/reductase family, but lacks the zinc-binding sites of the prototypical alcohol dehydrogenases of this group. Alcohol dehydrogenase in the liver converts ethanol and NAD+ to acetaldehyde and NADH, while in yeast and some other microorganisms ADH catalyzes the conversion acetaldehyde to ethanol in alcoholic fermentation. ADH is a member of the medium chain alcohol dehydrogenase family (MDR), which has a NAD(P)(H)-binding domain in a Rossmann fold of a beta-alpha form. The NAD(H)-binding region is comprised of 2 structurally similar halves, each of which contacts a mononucleotide. The N-terminal catalytic domain has a distant homology to GroES. These proteins typically form dimers (typically higher plants, mammals) or tetramers (yeast, bacteria), and have 2 tightly bound zinc atoms per subunit, a catalytic zinc at the active site and a structural zinc in a lobe of the catalytic domain. NAD(H) binding occurs in the cleft between the catalytic and coenzyme-binding domains at the active site, and coenzyme binding induces a conformational closing of this cleft. Coenzyme binding typically precedes and contributes to substrate binding. In human ADH catalysis, the zinc ion helps coordinate the alcohol, followed by deprotonation of a histidine, the ribose of NAD, a serine, then the alcohol, which allows the transfer of a hydride to NAD+, creating NADH and a zinc-bound aldehyde or ketone. In yeast and some bacteria, the active site zinc binds an aldehyde, polarizing it, and leading to the reverse reaction.
cd07509, HAD_PPase, inorganic pyrophosphatase similar to a human phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP). LHPP hydrolyzes nitrogen-phosphorus bonds in phospholysine, phosphohistidine and imidodiphosphate as well as oxygen-phosphorus bonds in inorganic pyrophosphate in vitro. This family also includes human haloacid dehalogenase like hydrolase domain containing 2 protine (HDHD2) a phosphatase which may be involved in polygenic hypertension. Members of this family belong 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.
pfam00583, Acetyltransf_1, Acetyltransferase (GNAT) family. This family contains proteins with N-acetyltransferase functions such as Elp3-related proteins.
cd07825, SRPBCC_7, Ligand-binding SRPBCC domain of an uncharacterized subfamily of proteins. Uncharacterized group of the SRPBCC (START/RHO_alpha_C/PITP/Bet_v1/CoxG/CalC) domain superfamily. SRPBCC domains have a deep hydrophobic ligand-binding pocket and they bind diverse ligands. SRPBCC domains include the steroidogenic acute regulatory protein (StAR)-related lipid transfer (START) domains of mammalian STARD1-STARD15, the C-terminal catalytic domains of the alpha oxygenase subunit of Rieske-type non-heme iron aromatic ring-hydroxylating oxygenases (RHOs_alpha_C), Class I and II phosphatidylinositol transfer proteins (PITPs), Bet v 1 (the major pollen allergen of white birch, Betula verrucosa), CoxG, CalC, and related proteins. Other members of the superfamily include PYR/PYL/RCAR plant proteins, the aromatase/cyclase (ARO/CYC) domains of proteins such as Streptomyces glaucescens tetracenomycin, and the SRPBCC domains of Streptococcus mutans Smu.440 and related proteins.
pfam02627, CMD, Carboxymuconolactone decarboxylase family. Carboxymuconolactone decarboxylase (CMD) EC:4.1.1.44 is involved in protocatechuate catabolism. In some bacteria a gene fusion event leads to expression of CMD with a hydrolase involved in the same pathway. In these bifunctional proteins CMD represents the C-terminal domain, pfam00561 represents the N-terminal domain.
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')
