MOLECULAR CHARACTERIZATION OF A MUTATION AFFECTING THE AMOUNT OF STREPTOCOCCUS-PNEUMONIAE PENICILLIN BINDING-PROTEIN-3

We have studied the molecular structure of the gene for the penicillin binding protein (PBP 3) of the Streptococcus pneumoniae wild-type str ain and a laboratory mutant strain that exhibits a reduced amount of t his protein on PBP gels, This mutation affects cefotaxime resistance w hen transferred into resistant strains. We have sequenced the PBP3 gen e, dacA, and upstream regions from the wild-type isogenic strain and t he laboratory mutant. We show that a deletion of one base-pair in the upstream sequence of this gene account for the phenotype by decreasing the amount of PBP3.