title: Characterization of the precursor of tetraether lipid biosynthesis in the thermoacidophilic archaeon Thermoplasma acidophilum.
abstract: Polar lipid biosynthesis in the thermoacidophilic archaeon Thermoplasma acidophilum was analyzed using terbinafine, an inhibitor of tetraether lipid biosynthesis. Cells of T. acidophilum were labeled with [(14)C]mevalonic acid, and their lipids were extracted and analyzed by two-dimensional thin-layer chromatography. Lipids labeled with [(14)C]mevalonic acid, [(14)C]glycerol, and [(32)P]orthophosphoric acid were extracted and hydrolyzed under different conditions to determine the structure of polar lipids. The polar lipids were estimated to be archaetidylglycerol, glycerophosphatidylcaldarchaetidylglycerol, caldarchaetidylglycerol, and beta- l-gulopyranosylcaldarchaetidylglycerol, the main polar lipid of T. acidophilum. Pulse and chase experiments with terbinafine revealed that one tetraether lipid molecule is synthesized by head-to-head condensation of two molecules of archaetidylglycerol and that a sugar group of tetraether phosphoglycolipid is expected to attach to the tetraether lipid core after head-to-head condensation in T. acidophilum. A precursor accumulated in the presence of terbinafine with a fast-atom-bombardment mass spectrometry peak m/z 806 was compatible with archaetidylglycerol. The relative height of the peak m/z 806 decreased after removal of the inhibitor. The results suggest that most of the precursor, archaetidylglycerol, is in fully saturated form.
authors.affiliation: Department of Molecular Biology, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Nemoto
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Shida
authors.forename: Haruo
authors.initials: H
authors.lastname: Shimada
authors.forename: Tairo
authors.initials: T
authors.lastname: Oshima
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yamagishi
mesh_terms: D002855:Chromatography, Thin Layer; D004987:Ethers; D005990:Glycerol / Q000737:chemistry; D006868:Hydrolysis; D050356:Lipid Metabolism; D008055:Lipids / Q000096:biosynthesis* / Q000737:chemistry; D013058:Mass Spectrometry; D008956:Models, Chemical; D013696:Temperature; D013822:Thermoplasma / Q000235:genetics*; D013997:Time Factors
chemical_list: D004987:Ethers; D008055:Lipids; D005990:Glycerol