Chemical structure of the cell wall of Mycobacterium smegmatis. I. Isolation and partial characterization of the peptidoglycan

Cell walls of were prepared by French press disruption and treatment with trypsin and chymotrypsin. Free lipids were extracted by organic solvents. Part of the bound lipids were solubilized by an alkaline treatment and most of the remaining lipids and neutral sugars by mild acid hydrolysis, leaving an insoluble residue which has the composition of a peptidoglycan. This residue was solubilized by AL1 enzyme. It was possible to isolate from the lysate a tripeptide Ala-Glu-DAP, three tetrapeptides Ala-Glu-DAP-Ala and also a tetrasaccharide and a disaccharide which give equimolar amounts of glucosamine and muramic acid after acid hydrolysis. The disaccharide differs from the typical [beta]-1,4-N-acetylglucosaminyl-N-acetylmuramic acid by its Rf values in various solvents.