Profiling of β-lactam selectivity for penicillin-binding proteins in Escherichia coli strain DC2.
Penicillin-binding proteins (PBPs) are integral players in bacterial cell division, and their catalytic activities can be monitored with β-lactam-containing chemical probes. Compounds that target a single PBP could provide important information about the specific role(s) of each enzyme, making identification of such molecules important. We evaluated 22 commercially available β-lactams for inhibition of the PBPs in live Escherichia coli strain DC2. Whole cells were titrated with β-lactam antibiotics and subsequently incubated with a fluorescent penicillin derivative, Bocillin-FL (Boc-FL), to label uninhibited PBPs. Protein visualization was accomplished by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) separation and fluorescent scanning. The examined β-lactams exhibited diverse PBP selectivities, with amdinocillin (mecillinam) showing selectivity for PBP2, aztreonam, piperacillin, cefuroxime, cefotaxime, and ceftriaxone for PBP3, and amoxicillin and cephalexin for PBP4. The remaining β-lactams did not block any PBPs in the DC2 strain of E. coli or inhibited more than one PBP at all examined concentrations in this Gram-negative organism.
Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Bloomington, Indiana, USA.
Ozden
O
Kocaoglu
Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Bloomington, Indiana, USA Department of Chemistry, Indiana University Bloomington, Bloomington, Indiana, USA carlsone@umn.edu.
Erin E
EE
Carlson
D000560:Amdinocillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001398:Aztreonam / Q000494:pharmacology; D002439:Cefotaxime / Q000494:pharmacology; D002444:Cefuroxime / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D046915:Penicillin-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D047090:beta-Lactams / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D046915:Penicillin-Binding Proteins; D047090:beta-Lactams; D001398:Aztreonam; D002439:Cefotaxime; D002444:Cefuroxime; D000560:Amdinocillin