Glucosylcaldarchaetidylglycerol, a minor phosphoglycolipid from Thermoplasma acidophilum

A novel phosphoglycolipid (GPL-K) was isolated from Thermoplasma acidophilum (ATCC 27658). The chemical components of GPL-K were analyzed by gas liquid chromatography and GC-MS. The sugar moiety of GPL-K and its anomeric region were analyzed by NMR assignment. The core lipid of GPL-K was caldarchaeol, and its main hydrocarbon chains were acyclic and monocyclic C40 biphytanyl. The polar head groups were α-glucose and glycerophosphate. The negative FAB-MS spectrum of GPL-K confirmed that the lipid peak of m/z 1614 consists of a caldarchaeol (including one cyclopentane ring), a hexose sugar, and a glycerophosphate. We have proposed the tentative structure of GPL-K.