(S)-2-AMINO-1,3-PROPANEDIOL-3-PHOSPHATE-CARRYING DIRADYLGLYCEROGLYCOLIPIDS - NOVEL MAJOR MEMBRANE-LIPIDS OF CLOSTRIDIUM-INNOCUUM

Two novel aminophosphoglycolipids (I, II) were isolated from Clostridi um innocuum which constitute 51% (I) and 15% (II) of total polar membr ane lipids. The structures, established by quantitative and methylatio n analyses, fast-atom-bombardment mass spectrometry, and one- and two- dimensional NMR spectroscopy, are (I) alactopyranosyl(1-2)alpha-D-gluc opyranosyl(1-3)dir and (II) an acylated derivative of (I) that carries an additional fatty acid ester on 06 of the glucosyl moiety. The ster eochemical configuration of the 2-amino-1,3-propanediol 3-phosphate re sidue was elucidated by conversion to N-acetylserine 3-phosphate, with subsequent release and identification of L-serine by HPLC. In additio n to diacylglycerol species, both aminophosphoglycolipids contain 15-3 2% 1-O-(alk-1-enyl)-2-O-acyl-glycerol species in which C-14, C-16, and C-18 vinyl ether are combined predominantly with unsaturated C-16 and C-18 fatty acid ester. Hydrogenation of the vinyl ether was required to desorb the alkyl, acyl-substituted species in fast-atom-bombardment mass spectrometry. Hydrogenation made it further possible to release the alkyl glycerols by acid hydrolysis and to locate the ether bond at 01 of the glycerol moiety. In contrast to the glycerophosphoglycolipi ds of other Gram-positive bacteria, the aminophosphoglycolipids are me tabolically not related to the lipoteichoic acid of C. innocuum and se rve, therefore, exclusively as major membrane components. Their large abundance among membrane lipids suggests bilayer-forming physicochemic al properties.