Chemical analysis of lipid-modified membrane proteins in Acholeplasma laidlawii

The lipid modification of membrane proteins was investigated in Acholeplasm a laidlawii by metabolic labeling and by chemical analysis. A S-glycerylcys teine residue was identified from membrane proteins and we reported the str ong preference for saturated acyl chains into the lipid modification. Diffe rential release of fatty acids revealed a ratio [(O-ester- + amide-bound ac yl chains)/O-ester-linked chains] close to 1.1 which suggests the involveme nt of only two O-ester linked fatty acids in the acylation process. Present data indicate that acyl proteins in A. laidlawii are true lipoproteins (ma inly diacylated) probably processed by a mechanism analogous to that descri bed for eubacteria and other mycoplasmas.