A General Structure for Cell Walls of Gram-Negative Bacteria

Abstract

THE cell walls of a number of Gram-negative bacteria have been shown to contain a mucopeptide component similar in, composition to that which forms a major fraction of the cell walls of Gram-positive bacteria¹. We have recently analysed the cell walls of an Escherichia coli mutant 26–26 requiring lysine for growth. A mucopeptide was isolated from cell walls by the procedure described by Mandelstam² which contained glucosamine, muramic acid, alanine, glutamic acid, diaminopimelic acid, serine, lysine and aspartic acid as major components. An ethanol-insoluble fraction from trichloroacetic acid extracts of cell-wall preparations contained on hydrolysis all the amino-acids found in the mucopeptide and also ribitol, phosphate and glucose. These results suggest that the cell wall of this organism contains the characteristic mucopeptide and in addition a ribitol teichoic acid³.