TIGR02397, DNA_polymerase_III_subunit_gamma, DNA polymerase III, subunit gamma and tau. This model represents the well-conserved first ~ 365 amino acids of the translation of the dnaX gene. The full-length product of the dnaX gene in the model bacterium E. coli is the DNA polymerase III tau subunit. A translational frameshift leads to early termination and a truncated protein subunit gamma, about 1/3 shorter than tau and present in roughly equal amounts. This frameshift mechanism is not necessarily universal for species with DNA polymerase III but appears conserved in the exterme thermophile Thermus thermophilis. [DNA metabolism, DNA replication, recombination, and repair].
cd08567, GDPD_SpGDE_like, Glycerophosphodiester phosphodiesterase domain of putative Silicibacter pomeroyi glycerophosphodiester phosphodiesterase and similar proteins. This subfamily corresponds to the glycerophosphodiester phosphodiesterase domain (GDPD) present in a group of uncharacterized bacterial glycerophosphodiester phosphodiesterases (GP-GDE, EC 3.1.4.46) and similar proteins. The prototype of this CD is a putative GP-GDE from Silicibacter pomeroyi (SpGDE). It shows high sequence similarity to Escherichia coli GP-GDE, which catalyzes the degradation of glycerophosphodiesters to produce sn-glycerol-3-phosphate (G3P) and the corresponding alcohols.
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.
COG0513, SrmB, Superfamily II DNA and RNA helicases [DNA replication, recombination, and repair / Transcription / Translation, ribosomal structure and biogenesis].
cd05799, PGM2, This CD includes PGM2 (phosphoglucomutase 2) and PGM2L1 (phosphoglucomutase 2-like 1). The mammalian PGM2 is thought to be a phosphopentomutase that catalyzes the conversion of the nucleoside breakdown products, ribose-1-phosphate and deoxyribose-1-phosphate to the corresponding 5-phosphopentoses. PGM2L1 is thought to catalyze the 1,3-bisphosphoglycerate-dependent synthesis of glucose 1,6-bisphosphate and other aldose-bisphosphates that serve as cofactors for several sugar phosphomutases and possibly also as regulators of glycolytic enzymes. PGM2 and PGM2L1 belong to the alpha-D-phosphohexomutase superfamily which includes several related enzymes that catalyze a reversible intramolecular phosphoryl transfer on their sugar substrates. Other members of this superfamily include phosphoglucosamine mutase (PNGM), phosphoacetylglucosamine mutase (PAGM), the bacterial phosphomannomutase ManB, the bacterial phosphoglucosamine mutase GlmM, and the bifunctional phosphomannomutase/phosphoglucomutase (PMM/PGM). Each of these enzymes has four domains with a centrally located active site formed by four loops, one from each domain. All four domains are included in this alignment model.
pfam07610, DUF1573, Protein of unknown function (DUF1573). These hypothetical proteins, from bacteria such as Rhodopirellula baltica, Bacteroides thetaiotaomicron, and Porphyromonas gingivalis, share a region of conserved sequence towards their N-termini.
pfam07695, 7TMR-DISM_7TM, 7TM diverse intracellular signalling. This entry represents the transmembrane region of the 7TM-DISM (7TM Receptors with Diverse Intracellular Signalling Modules).
pfam01062, Bestrophin, Bestrophin, RFP-TM, chloride channel. Bestrophin is a 68-kDa basolateral plasma membrane protein expressed in retinal pigment epithelial cells (RPE). It is encoded by the VMD2 gene, which is mutated in Best macular dystrophy, a disease characterized by a depressed light peak in the electrooculogram. VMD2 encodes a 585-amino acid protein with an approximate mass of 68 kDa which has been designated bestrophin. Bestrophin shares homology with the Caenorhabditis elegans RFP gene family, named for the presence of a conserved arginine (R), phenylalanine (F), proline (P), amino acid sequence motif. Bestrophin is a plasma membrane protein, localized to the basolateral surface of RPE cells consistent with a role for bestrophin in the generation or regulation of the EOG light peak. Bestrophin and other RFP family members represent a new class of chloride channels, indicating a direct role for bestrophin in generating the light peak. The VMD2 gene underlying Best disease was shown to represent the first human member of the RFP-TM protein family. More than 97% of the disease-causing mutations are located in the N-terminal RFP-TM domain implying important functional properties. The bestrophins are four-pass transmembrane chloride-channel proteins, and the RFP-TM or bestrophin domain extends from the N-terminus through approximately 350 amino acids and contains all of the TM domains as well as nearly all reported disease causing mutations. Interestingly, the RFP motif is not conserved evolutionarily back beyond Metazoa, neither is it in plant members.
cd03449, R_hydratase, (R)-hydratase [(R)-specific enoyl-CoA hydratase] catalyzes the hydration of trans-2-enoyl CoA to (R)-3-hydroxyacyl-CoA as part of the PHA (polyhydroxyalkanoate) biosynthetic pathway. (R)-hydratase contains a hot-dog fold similar to those of thioesterase II, and beta-hydroxydecanoyl-ACP dehydratase, MaoC dehydratase, Hydratase-Dehydrogenase-Epimerase protein (HDE), and the fatty acid synthase beta subunit. The active site lies within a substrate-binding tunnel formed by the (R)-hydratase homodimer. A subset of the bacterial (R)-hydratases contain a C-terminal phosphotransacetylase (PTA) domain.
TIGR02607, Virulence-associated_protein_I, addiction module antidote protein, HigA family. Members of this family form a distinct clade within the larger family HTH_3 of helix-turn-helix proteins, described by pfam01381. Members of this clade are strictly bacterial and nearly always shorter than 110 amino acids. This family includes the characterized member HigA, without which the killer protein HigB cannot be cloned. The hig (host inhibition of growth) system is noted to be unusual in that killer protein is uncoded by the upstream member of the gene pair. [Regulatory functions, DNA interactions, Regulatory functions, Protein interactions, Mobile and extrachromosomal element functions, Other].
cd00200, WD40, WD40 domain, found in a number of eukaryotic proteins that cover a wide variety of functions including adaptor/regulatory modules in signal transduction, pre-mRNA processing and cytoskeleton assembly; typically contains a GH dipeptide 11-24 residues from its N-terminus and the WD dipeptide at its C-terminus and is 40 residues long, hence the name WD40; between GH and WD lies a conserved core; serves as a stable propeller-like platform to which proteins can bind either stably or reversibly; forms a propeller-like structure with several blades where each blade is composed of a four-stranded anti-parallel b-sheet; instances with few detectable copies are hypothesized to form larger structures by dimerization; each WD40 sequence repeat forms the first three strands of one blade and the last strand in the next blade; the last C-terminal WD40 repeat completes the blade structure of the first WD40 repeat to create the closed ring propeller-structure; residues on the top and bottom surface of the propeller are proposed to coordinate interactions with other proteins and/or small ligands; 7 copies of the repeat are present in this alignment.
cd01104, HTH_MlrA-CarA, Helix-Turn-Helix DNA binding domain of the transcription regulators MlrA and CarA. Helix-turn-helix (HTH) transcription regulator MlrA (merR-like regulator A), N-terminal domain. The MlrA protein, also known as YehV, has been shown to control cell-cell aggregation by co-regulating the expression of curli and extracellular matrix production in Escherichia coli and Salmonella typhimurium. Its close homolog, CarA from Myxococcus xanthus, is involved in activation of the carotenoid biosynthesis genes by light. These proteins belong to the MerR superfamily of transcription regulators that promote expression of several stress regulon genes by reconfiguring the spacer between the -35 and -10 promoter elements. Their conserved N-terminal domains contain predicted HTH motifs that mediate DNA binding, while the dissimilar C-terminal domains bind specific coactivator molecules. Many MlrA- and CarA-like proteins in this group appear to lack the long dimerization helix seen in the N-terminal domains of typical MerR-like proteins.
cd17333, MFS_FucP_MFSD4_like, Bacterial fucose permease, eukaryotic Major facilitator superfamily domain-containing protein 4, and similar proteins. This family is composed of bacterial L-fucose permease (FucP), eukaryotic Major facilitator superfamily domain-containing protein 4 (MFSD4) proteins, and similar proteins. L-fucose permease facilitates the uptake of L-fucose across the boundary membrane with the concomitant transport of protons into the cell; it can also transport L-galactose and D-arabinose. The MFSD4 subfamily consists of two vertebrate members: MFSD4A and MFSD4B. The function of MFSD4A is unknown. MFSD4B is more commonly know as Sodium-dependent glucose transporter 1 (NaGLT1), a primary fructose transporter in rat renal brush-border membranes that also facilitates sodium-independent urea uptake. The FucP/MFSD4 family belongs 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.
cd11378, DUF296, Domain of unknown function found in archaea, bacteria, and plants. This domain is found in proteins that contain AT-hook motifs, which suggests a role in DNA-binding for the proteins as a whole. Three conserved histidine residues appear to form a zinc-binding site, and the domain has been observed to form homotrimers. It co-occurs with a thioredoxin-like domain in uncharacterized cyanobacterial proteins.
TIGR03866, PQQ_ABC_repeats, PQQ-dependent catabolism-associated beta-propeller protein. Members of this protein family consist of seven repeats each of the YVTN family beta-propeller repeat (see TIGR02276). Members occur invariably as part of a transport operon that is associated with PQQ-dependent catabolism of alcohols such as phenylethanol.
pfam10013, DUF2256, Uncharacterized protein conserved in bacteria (DUF2256). Members of this family of hypothetical bacterial proteins have no known function.
TIGR02765, deoxyribodipyrimidine_photolyase, cryptochrome, DASH family. Photolyases and cryptochromes are related flavoproteins. Photolyases harness the energy of blue light to repair DNA damage by removing pyrimidine dimers. Cryptochromes do not repair DNA and are presumed to act instead in some other (possibly unknown) process such as entraining circadian rhythms. This model describes the cryptochrome DASH subfamily, one of at least five major subfamilies, which is found in plants, animals, marine bacteria, etc. Members of this family bind both folate and FAD. They may show weak photolyase activity in vitro but have not been shown to affect DNA repair in vivo. Rather, DASH family cryptochromes have been shown to bind RNA (Vibrio cholerae VC1814), or DNA, and seem likely to act in light-responsive regulatory processes. [Cellular processes, Adaptations to atypical conditions].
cd07548, P-type_ATPase-Cd_Zn_Co_like, P-type heavy metal-transporting ATPase, similar to Bacillus subtilis CadA which appears to transport cadmium, zinc and cobalt but not copper out of the cell. Bacillus subtilis CadA/YvgW appears to transport cadmium, zinc and cobalt but not copper, out of the cell. Functions in metal ion resistance and cellular metal ion homeostasis. CadA/YvgW is also important for sporulation in B. subtilis, the significant specific expression of the cadA/yvgW gene during the late stage of sporulation, is controlled by forespore-specific sigma factor, sigma G, and mother cell-specific sigma factor, sigma E. This subfamily also includes Helicobacter pylori CadA an essential resistance pump with ion specificity towards Cd(2+), Zn(2+) and Co(2+), and Zn-transporting ATPase, ZiaA(N) in Synechocystis PCC 6803. Transcription of ziaA is induced by Zn under the control of the Zn responsive repressor ZiaR. This subclass of P-type ATPase is also referred to as CPx-type ATPases because their amino acid sequences contain a characteristic CPC or CPH motif associated with a stretch of hydrophobic amino acids and N-terminal ion-binding sequences. This subfamily belongs to the P-type ATPases, a large family of integral membrane transporters that are of critical importance in all kingdoms of life. They generate and maintain (electro-) chemical gradients across cellular membranes, by translocating cations, heavy metals and lipids, and are distinguished from other main classes of transport ATPases (F- , V- , and ABC- type) by the formation of a phosphorylated (P-) intermediate state in the catalytic cycle.
cd05233, SDR_c, classical (c) SDRs. 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 prostaglandin dehydrogenase (PGDH) numbering). In addition to the Tyr and Lys, there is often an upstream Ser (Ser-138, PGDH numbering) and/or an Asn (Asn-107, 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.
cd03505, Delta9-FADS-like, The Delta9 Fatty Acid Desaturase (Delta9-FADS)-like CD includes the delta-9 and delta-11 acyl CoA desaturases found in various eukaryotes including vertebrates, insects, higher plants, and fungi. The delta-9 acyl-lipid desaturases are found in a wide range of bacteria. These enzymes play essential roles in fatty acid metabolism and the regulation of cell membrane fluidity. Acyl-CoA desaturases are the enzymes involved in the CoA-bound desaturation of fatty acids. Mammalian stearoyl-CoA delta-9 desaturase is a key enzyme in the biosynthesis of monounsaturated fatty acids, and in yeast, the delta-9 acyl-CoA desaturase (OLE1) reaction accounts for all de nova unsaturated fatty acid production in Saccharomyces cerevisiae. These non-heme, iron-containing, ER membrane-bound enzymes are part of a three-component enzyme system involving cytochrome b5, cytochrome b5 reductase, and the delta-9 fatty acid desaturase. This complex catalyzes the NADH- and oxygen-dependent insertion of a cis double bond between carbons 9 and 10 of the saturated fatty acyl substrates, palmitoyl (16:0)-CoA or stearoyl (18:0)-CoA, yielding the monoenoic products palmitoleic (16:l) or oleic (18:l) acids, respectively. In cyanobacteria, the biosynthesis of unsaturated fatty acids is initiated by delta 9 acyl-lipid desaturase (DesC) which introduces the first double bond at the delta-9 position of a saturated fatty acid that has been esterified to a glycerolipid. This domain family has extensive hydrophobic regions that would be capable of spanning the membrane bilayer at least twice. Comparison of sequences also reveals the existence of three regions of conserved histidine cluster motifs that contain the residues: HXXXXH, HXXHH, and H/QXXHH. These histidine residues are reported to be catalytically essential and proposed to be the ligands for the iron atoms contained within the rat stearoyl CoA delta-9 desaturase. Some eukaryotic (Fungi, Euglenozoa, Mycetozoa, Rhodophyta) desaturase domains have an adjacent C-terminal cytochrome b5-like domain.
cd00156, REC, phosphoacceptor receiver (REC) domain of response regulators (RRs) and pseudo response regulators (PRRs). Two-component systems (TCSs) involving a sensor and a response regulator are used by bacteria to adapt to changing environments. Processes regulated by two-component systems in bacteria include sporulation, pathogenicity, virulence, chemotaxis, and membrane transport. Response regulators (RRs) share the common phosphoacceptor REC domain and different effector/output domains such as DNA, RNA, ligand-binding, protein-binding, or enzymatic domains. Response regulators regulate transcription, post-transcription or post-translation, or have functions such as methylesterases, adenylate or diguanylate cyclase, c-di-GMP-specific phosphodiesterases, histidine kinases, serine/threonine protein kinases, and protein phosphatases, depending on their output domains. The function of some output domains are still unknown. TCSs are found in all three domains of life - bacteria, archaea, and eukaryotes, however, the presence and abundance of particular RRs vary between the lineages. Archaea encode very few RRs with DNA-binding output domains; most are stand-alone REC domains. Among eukaryotes, TCSs are found primarily in protozoa, fungi, algae, and green plants. REC domains function as phosphorylation-mediated switches within RRs, but some also transfer phosphoryl groups in multistep phosphorelays.
TIGR01786, hemoglobin-haptoglobin-binding_protein, TonB-dependent hemoglobin/transferrin/lactoferrin receptor family protein. This model represents a family of TonB-dependent outer membrane receptor/transporters acting on iron-containing proteins such as hemoglobin, transferrin and lactoferrin. Two subfamily models with a narrower scope are contained within this model, the heme/hemoglobin receptor family protein model (TIGR01785) and the transferrin/lactoferrin receptor family model (TIGR01776). Accessions which score above trusted to this model while not scoring above trusted to the more specific models are most likely to be hemoglobin transporters. Nearly all of the species containing trusted hits to this model have access to hemoglobin, transferrin or lactoferrin or related proteins in their biological niche. [Transport and binding proteins, Cations and iron carrying compounds, Transport and binding proteins, Porins].
cd02947, TRX_family, TRX family; composed of two groups: Group I, which includes proteins that exclusively encode a TRX domain; and Group II, which are composed of fusion proteins of TRX and additional domains. Group I TRX is a small ancient protein that alter the redox state of target proteins via the reversible oxidation of an active site dithiol, present in a CXXC motif, partially exposed at the protein's surface. TRX reduces protein disulfide bonds, resulting in a disulfide bond at its active site. Oxidized TRX is converted to the active form by TRX reductase, using reducing equivalents derived from either NADPH or ferredoxins. By altering their redox state, TRX regulates the functions of at least 30 target proteins, some of which are enzymes and transcription factors. It also plays an important role in the defense against oxidative stress by directly reducing hydrogen peroxide and certain radicals, and by serving as a reductant for peroxiredoxins. At least two major types of functional TRXs have been reported in most organisms; in eukaryotes, they are located in the cytoplasm and the mitochondria. Higher plants contain more types (at least 20 TRX genes have been detected in the genome of Arabidopsis thaliana), two of which (types f amd m) are located in the same compartment, the chloroplast. Also included in the alignment are TRX-like domains which show sequence homology to TRX but do not contain the redox active CXXC motif. Group II proteins, in addition to either a redox active TRX or a TRX-like domain, also contain additional domains, which may or may not possess homology to known proteins.
TIGR03718, R_switched_Alx, integral membrane protein, TerC family. Rfam model RF00080 describes a structured RNA element called the yybP-ykoY leader, or SraF, which may precede one or several genes in a genome. Members of this highly hydrophobic protein family often are preceded by a yybP-ykoY leader, which may serve as a riboswitch. From the larger group of TerC homologs (pfam03741), this subfamily contains TerC itself from Alcaligenes sp. plasmid IncHI2 pMER610 and from Proteus mirabilis. It also contains the alkaline-inducible E. coli protein Alx, which unlike the two TerC examples is preceded by a yybP-ykoY leader.
cd01714, ETF_beta, The electron transfer flavoprotein (ETF) serves as a specific electron acceptor for various mitochondrial dehydrogenases. ETF transfers electrons to the main respiratory chain via ETF-ubiquinone oxidoreductase. ETF is an heterodimer that consists of an alpha and a beta subunit which binds one molecule of FAD per dimer . A similar system also exists in some bacteria. The homologous pair of proteins (FixA/FixB) are essential for nitrogen fixation. The beta subunit protein is distantly related to and forms a heterodimer with the alpha subunit.
pfam01145, Band_7, SPFH domain / Band 7 family. This family has been called SPFH, Band 7 or PHB domain. Recent phylogenetic analysis has shown this domain to be a slipin or Stomatin-like integral membrane domain conserved from protozoa to mammals.
cd07724, POD-like_MBL-fold, ETHE1 (PDO type I), persulfide dioxygenase A (PDOA, PDO type II) and related proteins; MBL-fold metallo-hydrolase domain. Persulfide dioxygenase (PDO, also known as sulfur dioxygenase, SDO, EC 1.13.11.18) is a non-heme iron-dependent oxygenase which catalyzes the oxidation of glutathione persulfide to glutathione and persulfite in the mitochondria. Mutations in ethe1 (the human PDO gene) are responsible for a rare autosomal recessive metabolic disorder called ethylmalonic encephalopathy. Arabidopsis thaliana ETHE1 is essential for embryo and endosperm development. Bacterial ETHE1-type PDOs are also called Type 1 PDOs. Type II PDOs (also called PDOAs), are mainly proteobacterial. These enzymes belong to the MBL-fold metallo-hydrolase superfamily which is comprised mainly of hydrolytic enzymes which carry out a variety of biological functions.
pfam02577, DNase-RNase, Bifunctional nuclease. This family is a bifunctional nuclease, with both DNase and RNase activity. It forms a wedge-shaped dimer, with each monomer being triangular in shape. A large groove at the thick end of the wedge contains a possible active site.
TIGR03903, TOMM_kin_cyc, TOMM system kinase/cyclase fusion protein. This model represents proteins of 1350 in length, in multiple species of Burkholderia, in Acidovorax avenae subsp. citrulli AAC00-1 and Delftia acidovorans SPH-1, and in multiple copies in Sorangium cellulosum, in genomic neighborhoods that include a cyclodehydratase/docking scaffold fusion protein (TIGR03882) and a member of the thiazole/oxazole modified metabolite (TOMM) precursor family TIGR03795. It has a kinase domain in the N-terminal 300 amino acids, followed by a cyclase homology domain, followed by regions without named domain definitions. It is a probable bacteriocin-like metabolite biosynthesis protein. [Cellular processes, Toxin production and resistance].
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')
