Evidence for involvement of penicillin-binding protein 3 in murein synthesis during septation but not during cell elongation.
Furazlocillin (1 microgram/ml) and piperacillin (5 microgram/ml) bound specifically to penicillin-binding protein 3 (PBP-3) and not to the other major PBPs in intact Escherichia coli cells. The effect of this specific binding to PBP-3 on murein synthesis of elongating and synchronously septating cells was investigated in two thermosensitive division mutants, E. coli BUG6 and E. coli JE10730, the latter possessing a thermolabile PBP-3. Synchronous cell division was induced by shifting the cultures from the nonpermissive temperature (42 degrees C) to 30 degrees C. Both [14C]diaminopimelic acid incorporation into murein of intact cells and [14C]N-acetylglucosamine incorporation into murein of cells permeabilized with ether was inhibited by an average of 42% in septating cells. In filaments growing at the nonpermissive temperature, we detected no inhibition and, frequently, a 10 to 15% stimulation of murein synthesis. The two drugs, at concentrations used in the above experiments, bound exclusively to PBP-3 both in elongating and septating intact cells and in ether-treated cells. These results support the hypothesis that PBP-3 activity is exclusively required for septal murein synthesis.
D001390:Azlocillin / Q000031:analogs & derivatives*; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000502:physiology*; D002455:Cell Division; D002701:Chloramphenicol / Q000494:pharmacology; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins; D006602:Hexosyltransferases; D048289:Imidazolidines; D002267:Muramoylpentapeptide Carboxypeptidase; D046915:Penicillin-Binding Proteins; D010406:Penicillins / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D010457:Peptidoglycan / Q000096:biosynthesis*; D046928:Peptidoglycan Glycosyltransferase; D010458:Peptidyl Transferases; D010878:Piperacillin
D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C478704:FtsI protein, E coli; D048289:Imidazolidines; D046915:Penicillin-Binding Proteins; D010406:Penicillins; D010457:Peptidoglycan; D002701:Chloramphenicol; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D046928:Peptidoglycan Glycosyltransferase; D002267:Muramoylpentapeptide Carboxypeptidase; D001390:Azlocillin; C017976:furazlocillin; D010878:Piperacillin