Complete polar lipid composition of Thermoplasma acidophilum HO-62 determined by high-performance liquid chromatography with evaporative light-scattering detection

Polar ether lipids of Thermoplasma acidophilum HO-62 were purified by, high-performance liquid chromatography with an evaporative light-scattering detector. Structures of purified lipids were investigated by capillary, gas chromatography, mass spectrometry, and nuclear magnetic resonance. Three types of ether lipids were found: phospholipids, glycolipids, and phosphoglycolipids. The two phospholipids had glycerophosphate as the phosphoester moiety. The seven glycolipids had different combinations of gulose, mannose, and glucose, which formed mono- or oligosaccharides. The eight phosphoglycolipids with two polar head groups contained glycerophosphate as the phosphoester moiety and gulose alone or gulose and mannose, which formed mono-or oligosaccharides, as the sugar moiety. Although gulose is an unusual sugar in nature, several glyco- and phosphoglycolipids contained gulose as one of the sugar moieties in Thermoplasma acidophilum. All the ether lipids had isopranoid chains of C-40 or C-20 with zero to three cyclopentane rings. The structures of these lipids including four new glycolipids and three new phosphoglycolipids were determined, and a glycosylation process for biosynthesis of these glycolipids was suggested.