IDENTIFICATION AND CHARACTERIZATION OF PBPA ENCODING BACILLUS-SUBTILIS PENICILLIN-BINDING PROTEIN 2A

Amino acid sequence analysis of tryptic peptides derived from purified penicillin-binding protein PBP2a of Bacillus subtilis identified the coding gene (now termed pbpA) as yqgF, which had been sequenced as par t of the B, subtilis genome project; pbpA encodes a 716-residue protei n with sequence similarity to class B high-molecular-weight PBPs, Use of a pbpA-lacZ fusion showed that pbpA was expressed predominantly dur ing vegetative growth, and the transcription start site was mapped usi ng primer extension analysis, Insertional mutagenesis of pbpA resulted in no changes in the growth rate or morphology of vegetative cells, i n the ability to produce heat-resistant spores, or in the ability to t rigger spore germination when compared to the wild type, However, pbpA spores were unable to efficiently elongate into cylindrical cells and were delayed significantly in spore outgrowth. This provides evidence that PBP2a is involved in the synthesis of peptidoglycan associated w ith cell wall elongation in B, subtilis.