Affiliation:
1. Max-Planck Institut für Molekulare Genetik, D-14185 Berlin,1 Germany
2. Department of Microbiology, University of Kaiserslautern, D-67663 Kaiserslautern,2 and
Abstract
ABSTRACT
One group of penicillin target enzymes, the class A high-molecular-weight penicillin-binding proteins (PBPs), are bimodular enzymes. In addition to a central penicillin-binding–transpeptidase domain, they contain an N-terminal putative glycosyltransferase domain. Mutations in the genes for each of the three
Streptococcus pneumoniae
class A PBPs, PBP1a, PBP1b, and PBP2a, were isolated by insertion duplication mutagenesis within the glycosyltransferase domain, documenting that their function is not essential for cellular growth in the laboratory. PBP1b PBP2a and PBP1a PBP1b double mutants could also be isolated, and both showed defects in positioning of the septum. Attempts to obtain a PBP2a PBP1a double mutant failed. All mutants with a disrupted
pbp2a
gene showed higher sensitivity to moenomycin, an antibiotic known to inhibit PBP-associated glycosyltransferase activity, indicating that PBP2a is the primary target for glycosyltransferase inhibitors in
S. pneumoniae.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology