The R gene product of bacteriophage λ is the murein transglycosylase

The radioactively labeled proteins synthesised in Escherichia coli minicells infected by bacteriophage λR and λR+ were compared by polyacrylamide gel electrophoresis. λR mutants, which have lost the ability to lyse host cells, lack a polypeptide of molecular weight 17.5 kD corresponding to the molecular weight of murein transglycosylase — a bacteriolytic enzyme from λ lysates which we have described previously. It has been shown by direct comparison using radio-labeled enzyme that transglycosylase comigrates with the R gene product. The enzyme was endetectable in induced cultures of E. coli W3350 suo (λcI857 Ram5) and C600 (λcI857 acR301), while it was present in a λR − + mutant lysate. We conclude that the transglycosylase is the R gene product.