Penicillin-binding proteins in Bacillus subtilis mutants

The penicillin-binding proteins (PBPs) from mutants of Bacillus subtilis were studied and related to morphology. In a previously described cloxacillin-resistant mutant of B. subtilis strain Porton, PBP 2a had an altered mobility by sodium dodecyl sulfate gel electrophoresis and was present in increased amounts. In addition, PBPs 1a and 1b were missing in this mutant. The only morphological change seen was a decrease in size of about 15%. Studies of two Triton-resistant morphological mutants of B. subtilis 168, Tr49 (small diameter) and Tr61 (helical form), revealed no change in the number of PBPs compared with that of the parent strain. However, PBPs 1a and 1b had an altered mobility in the mutant Tr49.