Cefotaxime-hydrolysing activity of the beta-lactamase of Klebsiella oxytoca D488 could be related to a threonine residue at position 140.
The chromosomally encoded beta-lactamase of Klebsiella oxytoca D483 strain, active against all third-generation cephalosporins but ceftazidime, was purified to homogeneity. The pure protein was digested by trypsin, Staphylococcus aureus V8 protease or proteinase Asp-N. Amino acid sequences of the HPLC-separated proteolytic peptides were determined by manual Edman degradation. Overlapping fragments gave the alignment of the 263 residues of the beta-lactamase which presented 90% homology with the beta-lactamase of the K. oxytoca E23004 strain and about 40% homology with the other enzymes of the structural class A. The cefotaximase activity might result from interaction of a threonine residue at position 140 (position 165 in the numbering of Ambler) with the oxyimino group of the antibiotic.
Reynaud
A
A
Muséum National Histoire Naturelle, CNRS URA 401, Paris, France.
Péduzzi
J
J
Barthélémy
M
M
Labia
R
R
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000378:metabolism; D002439:Cefotaxime / Q000378:metabolism*; D007709:Klebsiella / Q000201:enzymology*; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D013379:Substrate Specificity; D013912:Threonine / Q000737:chemistry*; D001618:beta-Lactamases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D013912:Threonine; D001618:beta-Lactamases; D002439:Cefotaxime