%0 Journal Article %A WORK, ELIZABETH %T The distribution of diamino acids in cell walls and its significance in bacterial taxonomy %D 1970 %J International Journal of Systematic and Evolutionary Microbiology, %V 20 %N 4 %P 425-433 %@ 1466-5034 %R https://doi.org/10.1099/00207713-20-4-425 %I Microbiology Society, %X ABSTRACT The distribution of diamino acids in cell walls of bacterial species bears some relation to taxonomy. The most widely distributed diamino acid is meso-diaminopimelic acid which is present in probably all Gram-negative species and in numerous other genera. L-lysine, also fairly common, is present in most Gram-positive cocci and in certain other species. Less frequent are DD or LL-diaminopimelic, β-OH - diaminopimelic, D or L ornithine, D or L diaminobutyric. The positions of these bifunctional amino acids in mucopep-tides (glycopeptides), the cross linked polymers of the walls, are described. Mucopeptides are divided into two types according to the site of termination of the cross-link from the D-alanine of an adjacent peptide chain. In type D, the site is the diamino acid which is located in the main peptide chain; in type G (less common) the site is the D-glutamic acid, and the diamino acid is in the cross link. Other differentiating features of types D and G include the optical configuration of the diamino acid, and the nature of the amino acid linking the peptide chain to the hexosamine backbone. %U https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/00207713-20-4-425