Characterization of caldarchaetidylglycerol analogs, dialkyl-type and trialkyl-type, from Thermoplasma acidophilum

The structures of three kinds of phospholipids (PL-X, PL-Y, and PL-T) isola ted from Thermoplasma acidophilum have been characterized. The core lipid o f PL-Y was caldarchaeol, and that of PL-X was archaeol. The composition of the hydrocarbon chains of the PL-T core lipid was C-20 phytane and C-40 iso prenoid in a molar ratio of 2 to 1. The major molecular species of the C-40 isoprenoid was acyclic without the cyclopentane ring. These three kinds of intact phospholipids commonly had glycerophosphate residues as polar head groups. The structure of PL-T was characterized as trialkyl-type caldarchae tidylglycerol, PL-Y as caldarchaetidylglycerol, and PL-X as archaetidylglyc erol.