cd16961, RMtype1_S_TRD-CR_like, Type I restriction-modification system specificity (S) subunit Target Recognition Domain-ConseRved domain (TRD-CR) and similar domains. The restriction-modification (RM) system S subunit generally 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 heteromeric enzyme complex composed of one DNA specificity (S) subunit (this family), two modification (M) subunits and two restriction (R) subunits. This superfamily represents a single TRD-CR unit; in addition to type I TRD-CR units, it includes RMtype1_S_TRD-CR_like domains of various putative Helicobacter type II restriction enzymes and methyltransferases, such as Hci611ORFHP and HfeORF12890P, as well as TRD-CR-like sequence-recognition domains of the M subunit of putative type I DNA methyltransferase such as M2.CinURNWORF2828P and M.Mae7806ORF3969P.
COG1585, COG1585, Membrane protein implicated in regulation of membrane protease activity [Posttranslational modification, protein turnover, chaperones / Intracellular trafficking and secretion].
cd17268, RMtype1_S_Ara36733I_TRD1-CR1_like, Type I restriction-modification system specificity (S) subunit Target Recognition Domain-ConseRved domain (TRD-CR), similar to S.Ara36733I TRD1-CR1 AND S.Ara36733I TRD2-CR2. Actinomyces radicidentis S subunit (S.Ara36733I) recognizes 5'... CGAGNNNNNCTG ... 3'. 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. It may also include TRD-CR-like sequence-recognition domains of various type II restriction enzymes and methyltransferases and type I DNA methyltransferases.
cd11333, AmyAc_SI_OligoGlu_DGase, Alpha amylase catalytic domain found in Sucrose isomerases, oligo-1,6-glucosidase (also called isomaltase; sucrase-isomaltase; alpha-limit dextrinase), dextran glucosidase (also called glucan 1,6-alpha-glucosidase), and related proteins. The sucrose isomerases (SIs) Isomaltulose synthase (EC 5.4.99.11) and Trehalose synthase (EC 5.4.99.16) catalyze the isomerization of sucrose and maltose to produce isomaltulose and trehalulose, respectively. Oligo-1,6-glucosidase (EC 3.2.1.10) hydrolyzes the alpha-1,6-glucosidic linkage of isomaltooligosaccharides, pannose, and dextran. Unlike alpha-1,4-glucosidases (EC 3.2.1.20), it fails to hydrolyze the alpha-1,4-glucosidic bonds of maltosaccharides. Dextran glucosidase (DGase, EC 3.2.1.70) hydrolyzes alpha-1,6-glucosidic linkages at the non-reducing end of panose, isomaltooligosaccharides and dextran to produce alpha-glucose.The common reaction chemistry of the alpha-amylase family enzymes is based on a two-step acid catalytic mechanism that requires two critical carboxylates: one acting as a general acid/base (Glu) and the other as a nucleophile (Asp). Both hydrolysis and transglycosylation proceed via the nucleophilic substitution reaction between the anomeric carbon, C1 and a nucleophile. Both enzymes contain the three catalytic residues (Asp, Glu and Asp) common to the alpha-amylase family as well as two histidine residues which are predicted to be critical to binding the glucose residue adjacent to the scissile bond in the substrates. The Alpha-amylase family comprises the largest family of glycoside hydrolases (GH), with the majority of enzymes acting on starch, glycogen, and related oligo- and polysaccharides. These proteins catalyze the transformation of alpha-1,4 and alpha-1,6 glucosidic linkages with retention of the anomeric center. The protein is described as having 3 domains: A, B, C. A is a (beta/alpha) 8-barrel; B is a loop between the beta 3 strand and alpha 3 helix of A; C is the C-terminal extension characterized by a Greek key. The majority of the enzymes have an active site cleft found between domains A and B where a triad of catalytic residues performs catalysis. Other members of this family have lost the catalytic activity as in the case of the human 4F2hc, or only have 2 residues that serve as the catalytic nucleophile and the acid/base, such as Thermus A4 beta-galactosidase with 2 Glu residues (GH42) and human alpha-galactosidase with 2 Asp residues (GH31). The family members are quite extensive and include: alpha amylase, maltosyltransferase, cyclodextrin glycotransferase, maltogenic amylase, neopullulanase, isoamylase, 1,4-alpha-D-glucan maltotetrahydrolase, 4-alpha-glucotransferase, oligo-1,6-glucosidase, amylosucrase, sucrose phosphorylase, and amylomaltase.
cd07062, Peptidase_S66_mccF_like, Microcin C7 self-immunity protein determines resistance to exogenous microcin C7. Microcin C7 self-immunity protein (mccF): MccF, a homolog of the LD-carboxypeptidase family, mediates resistance against exogenously added microcin C7 (MccC7), a ribosomally-encoded peptide antibiotic that contains a phosphoramidate linkage to adenosine monophosphate at its C-terminus. The plasmid-encoded mccF gene is transcribed in the opposite direction to the other five genes (mccA-E) and is required for the full expression of immunity but not for production. The catalytic triad residues (Ser, His, Glu) of LD-carboxypeptidase are also conserved in MccF, strongly suggesting that MccF shares the hydrolytic activity with LD-carboxypeptidases. Substrates of MccF have not been deduced, but could likely be microcin C7 precursors. The possible role of MccF is to defend producer cells against exogenous microcin from re-entering after having been exported. It is suggested that MccF is involved in microcin degradation or sequestration in the periplasm.
cd14014, STKc_PknB_like, Catalytic domain of bacterial Serine/Threonine kinases, PknB and similar proteins. STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. This subfamily includes many bacterial eukaryotic-type STKs including Staphylococcus aureus PknB (also called PrkC or Stk1), Bacillus subtilis PrkC, and Mycobacterium tuberculosis Pkn proteins (PknB, PknD, PknE, PknF, PknL, and PknH), among others. S. aureus PknB is the only eukaryotic-type STK present in this species, although many microorganisms encode for several such proteins. It is important for the survival and pathogenesis of S. aureus as it is involved in the regulation of purine and pyrimidine biosynthesis, cell wall metabolism, autolysis, virulence, and antibiotic resistance. M. tuberculosis PknB is essential for growth and it acts on diverse substrates including proteins involved in peptidoglycan synthesis, cell division, transcription, stress responses, and metabolic regulation. B. subtilis PrkC is located at the inner membrane of endospores and functions to trigger spore germination. Bacterial STKs in this subfamily show varied domain architectures. The well-characterized members such as S. aureus and M. tuberculosis PknB, and B. subtilis PrkC, contain an N-terminal cytosolic kinase domain, a transmembrane (TM) segment, and mutliple C-terminal extracellular PASTA domains. The PknB subfamily is part of a larger superfamily that includes the catalytic domains of other protein STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.
cd09075, DNase1-like, Deoxyribonuclease 1 and related proteins. This family includes Deoxyribonuclease 1 (DNase1, EC 3.1.21.1) and related proteins. DNase1, also known as DNase I, is a Ca2+, Mg2+/Mn2+-dependent secretory endonuclease, first isolated from bovine pancreas extracts. It cleaves DNA preferentially at phosphodiester linkages next to a pyrimidine nucleotide, producing 5'-phosphate terminated polynucleotides with a free hydroxyl group on position 3'. It generally produces tetranucleotides. DNase1 substrates include single-stranded DNA, double-stranded DNA, and chromatin. This enzyme may be responsible for apoptotic DNA fragmentation. Other deoxyribonucleases in this subfamily include human DNL1L (human DNase I lysosomal-like, also known as DNASE1L1, Xib and DNase X ), human DNASE1L2 (also known as DNAS1L2), and DNASE1L3 (also known as DNAS1L3, nhDNase, LS-DNase, DNase Y, and DNase gamma). DNASE1L3 is also implicated in apoptotic DNA fragmentation. DNase1 is also a cytoskeletal protein which binds actin. A recombinant form of human DNase1 is used as a mucoactive therapy in patients with cystic fibrosis; it hydrolyzes the extracellular DNA in sputum and reduces its viscosity. Mutations in the gene encoding DNase1 have been associated with Systemic Lupus Erythematosus, a multifactorial autoimmune disease. This family also includes a subfamily of mostly uncharacterized proteins, which includes Mycoplasma pulmonis MnuA, a membrane-associated nuclease. The in vivo role of MnuA is as yet undetermined. This family belongs to the large EEP (exonuclease/endonuclease/phosphatase) superfamily that contains functionally diverse enzymes that share a common catalytic mechanism of cleaving phosphodiester bonds.
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')
