COG0745, OmpR, Response regulators consisting of a CheY-like receiver domain and a winged-helix DNA-binding domain [Signal transduction mechanisms / Transcription].
cd07263, VOC_like, uncharacterized subfamily of vicinal oxygen chelate (VOC) family. The vicinal oxygen chelate (VOC) superfamily is composed of structurally related proteins with paired beta.alpha.beta.beta.beta motifs that provide a metal coordination environment with two or three open or readily accessible coordination sites to promote direct electrophilic participation of the metal ion in catalysis. VOC domain is found in a variety of structurally related metalloproteins, including the bleomycin resistance protein, glyoxalase I, and type I ring-cleaving dioxygenases. A bound metal ion is required for protein activities for the members of this superfamily. A variety of metal ions have been found in the catalytic centers of these proteins including Fe(II), Mn(II), Zn(II), Ni(II) and Mg(II). The protein superfamily contains members with or without domain swapping. The proteins of this family share three conserved metal binding amino acids with the type I extradiol dioxygenases, which shows no domain swapping.
pfam15188, CCDC-167, Coiled-coil domain-containing protein 167. The function of this family of coiled-coil domains, has not, as yet, been determined. Members of this family remain uncharacterized. This family of proteins is found in eukaryotes. Proteins in this family are typically between and 103 amino acids in length.
pfam04024, PspC, PspC domain. This family includes Phage shock protein C (PspC) that is thought to be a transcriptional regulator. The presumed domain is 60 amino acid residues in length.
cd00371, HMA, Heavy-metal-associated domain (HMA) is a conserved domain of approximately 30 amino acid residues found in a number of proteins that transport or detoxify heavy metals, for example, the CPx-type heavy metal ATPases and copper chaperones. HMA domain contains two cysteine residues that are important in binding and transfer of metal ions, such as copper, cadmium, cobalt and zinc. In the case of copper, stoichiometry of binding is one Cu+ ion per binding domain. Repeats of the HMA domain in copper chaperone has been associated with Menkes/Wilson disease due to binding of multiple copper ions.
TIGR02135, Uncharacterized_protein, phosphate transport system regulatory protein PhoU. This model describes PhoU, a regulatory protein of unknown mechanism for high-affinity phosphate ABC transporter systems. The protein consists of two copies of the domain described by pfam01895. Deletion of PhoU activates constitutive expression of the phosphate ABC transporter and allows phosphate transport, but causes a growth defect and so likely has some second function. [Regulatory functions, Other, Transport and binding proteins, Anions].
COG0601, DppB, ABC-type dipeptide/oligopeptide/nickel transport systems, permease components [Amino acid transport and metabolism / Inorganic ion transport and metabolism].
cd07106, ALDH_AldA-AAD23400, Streptomyces aureofaciens putative aldehyde dehydrogenase AldA (AAD23400)-like. Putative aldehyde dehydrogenase, AldA, from Streptomyces aureofaciens (locus AAD23400) and other similar sequences are present in this CD.
cd07093, ALDH_F8_HMSADH, Human aldehyde dehydrogenase family 8 member A1-like. In humans, the aldehyde dehydrogenase family 8 member A1 (ALDH8A1) protein functions to convert 9-cis-retinal to 9-cis-retinoic acid and has a preference for NAD+. Also included in this CD is the 2-hydroxymuconic semialdehyde dehydrogenase (HMSADH) which catalyzes the conversion of 2-hydroxymuconic semialdehyde to 4-oxalocrotonate, a step in the meta cleavage pathway of aromatic hydrocarbons in bacteria. Such HMSADHs seen here are: XylG of the TOL plasmid pWW0 of Pseudomonas putida, TomC of Burkholderia cepacia G4, and AphC of Comamonas testosterone.
TIGR02312, 2-keto-4-pentenoate_hydratase, 2-oxo-hepta-3-ene-1,7-dioic acid hydratase. This model represents the enzyme which hydrates the double bond of 2-oxo-hepta-3-ene-1,7-dioic acid to form 4-hydroxy-2-oxo-heptane-1,7-dioic acid in the catabolism of 4-hydroxyphenylacetic acid. The gene for this enzyme is generally found adjacent to other genes of this pathway in an apparent operon.
pfam08818, DUF1801, Domain of unknown function (DU1801). This large family of bacterial proteins is uncharacterized. They contain a presumed domain about 110 amino acids in length.
cd18678, PIN_MtVapC25_VapC33-like, VapC-like PIN domain of Mycobacterium tuberculosis VapC25, VapC33, and related proteins. This subfamily includes the Virulence associated protein C (VapC)-like PIN (PilT N terminus) domain of Mycobacterium tuberculosis VapC25, VapC29, VapC33, VapC37, and VapC39 toxins. It belongs to the VapC-like family of the PIN domain nuclease superfamily. VapC is a PIN-domain ribonuclease toxin from prokaryotic VapBC toxin-antitoxin (TA) systems. VapB is a transcription factor-like protein antitoxin acting as an inhibitor. Other members of the VapC-like nuclease family include FitB toxin of the FitAB TA system, eukaryotic ribonucleases such as Smg6, ribosome assembly factor NOB1, exosome subunit Rrp44 endoribonuclease and rRNA-processing protein Fcf1. The structural properties of the PIN domain indicate its active center, consisting of three highly conserved catalytic residues which coordinate metal ions; in some members, additional metal coordinating residues can be found while some others lack several of these key catalytic residues. The PIN active site is geometrically similar in the active center of structure-specific 5' nucleases, PIN-domain ribonucleases of eukaryotic rRNA editing proteins, and bacterial toxins of toxin-antitoxin (TA) operons.
TIGR03695, menH_SHCHC, 2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate synthase. This protein catalyzes the formation of SHCHC, or (1 R,6 R)-2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate, by elmination of pyruvate from 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylate (SEPHCHC). Note that SHCHC synthase activity previously was attributed to MenD, which in fact is SEPHCHC synthase. [Biosynthesis of cofactors, prosthetic groups, and carriers, Menaquinone and ubiquinone].
cd17320, MFS_MdfA_MDR_like, Multidrug transporter MdfA and similar multidrug resistance (MDR) transporters of the Major Facilitator Superfamily. This family is composed of bacterial multidrug resistance (MDR) transporters including several proteins from Escherichia coli such as MdfA (also called chloramphenicol resistance pump Cmr), EmrD, MdtM, MdtL, bicyclomycin resistance protein (also called sulfonamide resistance protein), and the uncharacterized inner membrane transport protein YdhC. EmrD is a proton-dependent secondary transporter, first identified as an efflux pump for uncouplers of oxidative phosphorylation. It expels a range of drug molecules and amphipathic compounds across the inner membrane of E. coli. Similarly, MdfA is a secondary multidrug transporter that exports a broad spectrum of structurally and electrically dissimilar toxic compounds. These MDR transporters are drug/H+ antiporters (DHA) belonging to the Major Facilitator Superfamily (MFS) of membrane transport proteins, which are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement.
cd08496, PBP2_NikA_DppA_OppA_like_9, 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 can bind 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.
