Complementation of growth defect in an ampC deletion mutant of Escherichia coli.
beta-Lactamase genes of class-A (Rtem) and class-C (ampC) were placed under control of an inducible tac-promoter and expressed in Escherichia coli. Expression of RTEM had no observable effect on the growth properties of E. coli strains HB101 (ampC+) or MI1443 (delta ampC). E. coli MI1443 exhibited a decline in growth rate at mid-exponential phase which could be delayed by expression of AmpC at early-exponential phase. AmpC expression otherwise inhibited growth, particularly during the transition into exponential phase where growth was prevented altogether. We suggest that the AmpC beta-lactamase, but not RTEM, may have an additional cellular function as a peptidoglycan hydrolase.
Bishop
R E
RE
Department of Biochemistry, University of Alberta, Edmonton, Canada.
Weiner
J H
JH
D001483:Base Sequence; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D017353:Gene Deletion; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D008969:Molecular Sequence Data; D001618:beta-Lactamases / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology
D001618:beta-Lactamases