Zur Biosynthese des formgebenden Elements der Bakterienzellwand

Abstract

Two stages in murein-biosynthesis — first, the partial degradation of the preexistent murein and second, the neosynthesis immediately following it under normal conditions — can be separated by DAP *-starvation of the DAP-dependent mutant of E. coli W 173-25. In order to investigate the function of mureinhydrolases in murein-biosynthesis, the degradation of murein in growing cells has been studied using a new method. Evidence is presented which indicates that a muramylendopeptidase plays a major role in the process. The activity of this enzyme is revealed by a conversion of the cells into spheroplasts upon DAP-starvation. A hypothesis concerning the insertion of new murein moieties due to transpeptidation by this enzyme is discussed.