Chloramphenicol acetyltransferase is a bacterial enzyme that detoxifies the antibiotic chloramphenicol and is responsible for chloramphenicol resistance in bacteria. This enzyme covalently attaches an acetyl group from acetyl-CoA to chloramphenicol, which prevents chloramphenicol from binding to ribosomes. A histidine residue, located in the C-terminal section of the enzyme, plays a central role in its catalytic mechanism.
Oxaloacetate decarboxylase is a carboxy-lyase involved in the conversion of oxaloacetate into pyruvate.
Carbamoyl phosphate synthetase catalyzes the ATP-dependent synthesis of carbamoyl phosphate from glutamine or ammonia and bicarbonate. This enzyme catalyzes the reaction of ATP and bicarbonate to produce carboxy phosphate and ADP. Carboxy phosphate reacts with ammonia to give carbamic acid. In turn, carbamic acid reacts with a second ATP to give carbamoyl phosphate plus ADP.
In molecular biology, Adenylosuccinate synthase is an enzyme that plays an important role in purine biosynthesis, by catalysing the guanosine triphosphate (GTP)-dependent conversion of inosine monophosphate (IMP) and aspartic acid to guanosine diphosphate (GDP), phosphate and N(6)-(1,2-dicarboxyethyl)-AMP. Adenylosuccinate synthetase has been characterised from various sources ranging from Escherichia coli to vertebrate tissues. In vertebrates, two isozymes are present: one involved in purine biosynthesis and the other in the purine nucleotide cycle.
In enzymology, a L-fucose isomerase is an enzyme that catalyzes the chemical reaction
In enzymology, a dUTP diphosphatase (EC 3.6.1.23) is an enzyme that catalyzes the chemical reaction
In enzymology, an ATP phosphoribosyltransferase is an enzyme that catalyzes the chemical reaction
Heat-stable enterotoxins (STs) are secretory peptides produced by some bacterial strains, such as enterotoxigenic Escherichia coli which are in general toxic to animals.
In molecular biology, the ter site, also known as DNA replication terminus binding-site, refers to a protein domain which binds to the DNA replication terminus site. Ter-binding proteins are found in some bacterial species, and include the tus protein which is part of the common ter-tus binding domain. They are required for the termination of DNA replication and function by binding to DNA replication terminator sequences, thus preventing the passage of replication forks. The termination efficiency is affected by the affinity of a particular protein for the terminator sequence.
In molecular biology, the amino acid kinase domain is a protein domain. It is found in protein kinases with various specificities, including the aspartate, glutamate and uridylate kinase families. In prokaryotes and plants the synthesis of the essential amino acids lysine and threonine is predominantly regulated by feed-back inhibition of aspartate kinase (AK) and dihydrodipicolinate synthase (DHPS). In Escherichia coli, thrA, metLM, and lysC encode aspartokinase isozymes that show feedback inhibition by threonine, methionine, and lysine, respectively. The lysine-sensitive isoenzyme of aspartate kinase from spinach leaves has a subunit composition of 4 large and 4 small subunits.
In molecular biology, the ars operon is an operon found in several bacterial taxon. It is required for the detoxification of arsenate, arsenite, and antimonite. This system transports arsenite and antimonite out of the cell. The pump is composed of two polypeptides, the products of the arsA and arsB genes. This two-subunit enzyme produces resistance to arsenite and antimonite. Arsenate, however, must first be reduced to arsenite before it is extruded. A third gene, arsC, expands the substrate specificity to allow for arsenate pumping and resistance. ArsC is an approximately 150-residue arsenate reductase that uses reduced glutathione (GSH) to convert arsenate to arsenite with a redox active cysteine residue in the active site. ArsC forms an active quaternary complex with GSH, arsenate, and glutaredoxin 1 (Grx1). The three ligands must be present simultaneously for reduction to occur.
In molecular biology, the CLP protease family is a family of serine peptidases belong to the MEROPS peptidase family S14. ClpP is an ATP-dependent protease that cleaves a number of proteins, such as casein and albumin. It exists as a heterodimer of ATP-binding regulatory A and catalytic P subunits, both of which are required for effective levels of protease activity in the presence of ATP, although the P subunit alone does possess some catalytic activity.
In molecular biology, the cytotoxic necrotising factor family of proteins includes bacterial cytotoxic necrotising factor proteins and the related dermonecrotic toxin (DNT) from Bordetella species. Cytotoxic necrotizing factor 1 (CNF1) is a toxin whose structure from Escherichia coli revealed a 4-layer alpha/beta/beta/alpha structure containing mixed beta-sheets. CNF1 is expressed in strains of E. coli causing uropathogenic and neonatal meningitis. CNF1 alters host cell actin cytoskeleton and promotes bacterial invasion of the blood–brain barrier endothelial cells. CNF1 belongs to a unique group of large cytotoxins that cause constitutive activation of Rho guanosine triphosphatases (GTPases), which are key regulators of the actin cytoskeleton.
In molecular biology, the DHH phosphatase family is a family of phosphoesterases. The family includes Drosophila prune protein and bacterial RecJ exonuclease. The RecJ protein of Escherichia coli plays an important role in a number of DNA repair and recombination pathways. RecJ catalyses processive degradation of single-stranded DNA in a 5'-to-3' direction. Sequences highly related to those encoding RecJ can be found in many of the eubacterial genomes sequenced to date.
In molecular biology, the heat-labile enterotoxin family includes Escherichia coli heat-labile enterotoxin (Elt) and cholera toxin (Ctx) secreted by Vibrio cholerae.
In molecular biology, the F-actin capping protein is a protein which binds in a calcium-independent manner to the fast-growing ends of actin filaments, thereby blocking the exchange of subunits at these ends. Unlike gelsolin and severin this protein does not sever actin filaments. The F-actin capping protein is a heterodimer composed of two unrelated subunits: alpha and beta. Neither of the subunits shows sequence similarity to other filament-capping proteins. The alpha subunit is a protein of about 268 to 286 amino acid residues and the beta subunit is approximately 280 amino acids, their sequences are well conserved in eukaryotic species.
In molecular biology the FGGY carbohydrate kinase family is a family of evolutionary related carbohydrate kinase enzymes. These enzymes include L-fucolokinase EC 2.7.1.51 ; gluconokinase EC 2.7.1.12 ; glycerol kinase EC 2.7.1.30 ; xylulokinase EC 2.7.1.17 ; D-ribulose kinase EC 2.7.1.47 ; and L-xylulose kinase EC 2.7.1.53. These enzymes are proteins of from 480 to 520 amino acid residues.
In molecular biology, the glutaredoxin 2 family is a family of bacterial glutaredoxins. Unlike other glutaredoxins, glutaredoxin 2 (Grx2) cannot reduce ribonucleotide reductase. Grx2 has significantly higher catalytic activity in the reduction of mixed disulphides with glutathione (GSH) compared with other glutaredoxins. The active site residues (Cys9-Pro10-Tyr11-Cys12, in Escherichia coli Grx2, which are found at the interface between the N- and C-terminal domains are identical to other glutaredoxins, but there is no other similarity between glutaredoxin 2 and other glutaredoxins. Grx2 is structurally similar to glutathione-S-transferases, but there is no obvious sequence similarity. The inter-domain contacts are mainly hydrophobic, suggesting that the two domains are unlikely to be stable on their own. Both domains are needed for correct folding and activity of Grx2. It is thought that the primary function of Grx2 is to catalyse reversible glutathionylation of proteins with GSH in cellular redox regulation including the response to oxidative stress. These enzymes are not related to GLRX2.
In molecular biology, the hydrogenase maturation protease family is a family of aspartic endopeptidases belonging to MEROPS family A31.
In molecular biology, group IV pyridoxal-dependent decarboxylases are a family of enzymes comprising ornithine decarboxylase EC 4.1.1.17, lysine decarboxylase EC 4.1.1.18, arginine decarboxylase EC 4.1.1.19 and diaminopimelate decarboxylaseEC 4.1.1.20. It is also known as the Orn/Lys/Arg decarboxylase class-II family.
