The Murein‐Lipoprotein Linkage in the Cell Wall of Escherichia coli

Abstract

After digestion of the murein‐lipoprotein complex (rigid layer) of the E. coli cell wall with lysozyme the solubilized lipoprotein contained 2 disaccharide units of the murein per 1 lipoprotein molecule. From purely enzymatic degradation of the murein‐lipoprotein complex with pronase and lysozyme the peptide GlcNAc‐MurNAc‐l‐Ala‐d‐Glu‐Dpm‐Lys‐Arg was isolated, where MurNAc =N‐acetyl‐muramic acid and Dpm =meso‐2,6‐diaminopimelic acid. The missing d‐alanine in this repeating unit of the murein is replaced by the lysyl‐arginine dipeptide of the lipoprotein. The lipoprotein molecules are therefore linked to the carboxyl group of the optical l‐center of the diaminopimelic acid of the murein. Copyright © 1970, Wiley Blackwell. All rights reserved