The sulfated polysaccharide-peptidoglycan complex from an Arthrobacter species: characterization of the linkage...

Further structural features of the sulfated polysaccharide-peptidoglycan complex, which is produced by an Arthrobacter sp. and contains phosphorus as its minor component, were investigated. Phosphoric acid esters such as D-glucose 6-phosphate, glycerol 1-phosphate and muramic acid phosphate were isolated from the acid hydrolysate of the complex. On mild acid treatment, the complex became positive for both the Morgan-Elson reaction and acid phosphatase digestion. The mild acid hydrolysate readily formed the Morgan-Elson chromogen on heating at pH 7, indicating release of terminal reducing N-acetylglucosamine substituted on C-3 by adjacent sugars, and its release was accompanied by that of phosphomonoester. The complex released peptidoglycan fragments on the mild acid treatment, together with acid-degraded, sulfated polysaccharide chains with terminal reducing N-acetylglucosamine. A large proportion of phosphorus in the complex was shown to occur in the sulfated polysaccharide chains, and the rest as muramic acid phosphate in the peptidoglycan fragments. After mild acid treatment of the complex, 50% of total phosphorus was released as inorganic phosphate on phosphatase digestion of the hydrolysate. These results suggest that the sulfated polysaccharide chains, which are additionally phosphorylated to a low degree, are linked to the peptidoglycan fragments through acid-labile phosphodiester linkages, probably between (1 leads to 3)-linked N-acetylglucosamine 1-phosphate and muramic acid.