Chromosomally encoded cephalosporin-hydrolyzing beta-lactamase of Proteus vulgaris RO104 belongs to Ambler's class A.
Proteus vulgaris RO104 strain produces a chromosomally encoded beta-lactamase that confers resistance to various beta-lactam antibiotics including methoxyimino third-generation cephalosporins. The beta-lactamase hydrolyzes first- and second-generation cephalosporins efficiently and cefotaxime to a lesser extent. Catalytic activity is inhibited by low concentrations of clavulanic acid and sulbactam. By its broad-spectrum substrate profile, beta-lactamase of Proteus vulgaris RO104 belongs to the group 2e defined by Bush. The protein purified to homogeneity by a four-step procedure was characterized by a pI of 8.31 and a specific activity of 1200 U/mg. The beta-lactamase was digested by trypsin, endoproteinase Asp-N and chymotrypsin. Amino-acid sequence determinations of the resulting peptides allowed the alignment of the 271 amino-acid residues of the protein which did not contain any cysteine residue. From amino-acid sequence comparisons, Proteus vulgaris RO104 beta-lactamase was found to share about 68% identity with the chromosomally mediated beta-lactamases of Klebsiella oxytoca D488 and E23004. Therefore, the cephalosporin-hydrolyzing beta-lactamase of Proteus vulgaris RO104 belongs to Ambler's class A.
Péduzzi
J
J
Muséum National Histoire Naturelle, CNRS URA 401, Paris, France.
Reynaud
A
A
Baron
P
P
Barthélémy
M
M
Labia
R
R
D000595:Amino Acid Sequence; D002511:Cephalosporins / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D011514:Proteus vulgaris / Q000201:enzymology / Q000235:genetics*; D016415:Sequence Alignment; D001618:beta-Lactamases / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification
D002511:Cephalosporins; D001618:beta-Lactamases