The amino acid sequence of the L-glutamic acid containing mureins of Micrococcus luteus and M. freudenreichii

The mureins (peptidoglycans) known so far, contain 1 mole of D-glutamic acid per mole of murein subunit (1, 2, 3). Studying the mureins of micrococci, we found two strains, which contain 2 moles of glutamic acid per subunit, one of the D- and one of the L-configuration. This paper describes experiments which show, that in both strains the D-glutamic acid is part of the tetrapeptide, attached to muramic acid as usually, while the L-glutamic acid takes part in the cross linkages. The interpeptide bridge between the carboxyl group of D-alanine of one tetrapeptide and the ε-amino group of lysine of another tetrapeptide consists of {A figure is presented}-L-glutamyl-glycine in M. luteus and of {A figure is presented}-L-glutamyl-L-alanine in M. freudenreichii.