Penicillin binding proteins in Listeria monocytogenes.
Membranes of Listeria were obtained from protoplasts and treated with 125I-ampicillin as probe, at different concentrations. Eight bands, corresponding to proteins labelled with the probe were detected their molecular weight ranged from 38,000 to 100,000, being the predominant ones at 95,000; 85,000; 60,000; 49,000 and 38,000. The copy number of each PBP was also estimated. By means of competitive experiments the binding pattern of ampicillin, mecillinam, piperacillin, cefalotin, cefaloridine, cefoxitin, cefotaxime, azthreonam and imipenem was studied. The most effective binding was obtained with ampicillin, piperacillin and imipenem. Cefotaxime, and particularly cefoxitin, present an extremely low binding ability. The amount of antibiotic concentration preventing an effective label by the radioactive probe to the detected penicillin binding proteins seems to correlate with the lethal concentration of the different antibiotics on Listeria monocytogenes and explains the natural resistance of this genus to certain beta-lactamic compounds.
Vicente
M F
MF
Department of Microbiology, Ramon y Cajal Hospital, CSIC-UAM, Madrid, Spain.
Berenguer
J
J
de Pedro
M A
MA
Pérez-Diaz
J C
JC
Baquero
F
F
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D004352:Drug Resistance, Microbial; D006602:Hexosyltransferases; D007769:Lactams; D008089:Listeria monocytogenes / Q000187:drug effects / Q000378:metabolism*; D008970:Molecular Weight; D002267:Muramoylpentapeptide Carboxypeptidase / Q000737:chemistry / Q000378:metabolism*; D046915:Penicillin-Binding Proteins; D010406:Penicillins / Q000378:metabolism*; D010458:Peptidyl Transferases
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D007769:Lactams; D046915:Penicillin-Binding Proteins; D010406:Penicillins; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase