RESUMO
The main polar lipid (MPL) of Thermoplasma acidophilum has been purified and its structure determined. NMR, mass spectrometry, and capillary gas chromatography-mass spectrometry experiments have shown that the previously unidentified sugar moiety of MPL is the rare sugar L-gulose. MPL is thus a tetraether lipid with cyclopentane rings and head groups of phosphoglycerol, as previously reported, and beta-L-gulopyranose. Further, MPL is also the dominant lipid found in lipid extracts from another species of the Thermoplasma genus, T. volcanium, suggesting that L-gulose may represent a dominant sugar moiety of the polar lipids biosynthesized by this archaeobacterial genus. Minor phospholipids were tentatively identified as diether and hydroxydiether analogs of phosphatidylglycerol, and phosphatidylinositol.
Assuntos
Glicolipídeos/química , Hexoses/análise , Thermoplasma/química , Glicolipídeos/isolamento & purificação , Espectroscopia de Ressonância Magnética , Espectrometria de MassasRESUMO
Preparation of the following glycosides is described: 2-aminoethyl beta-D-glycosides of (A) 2-acetamido-3,4,6-trio-O-acetyl-2-deoxy-D-glucopyranose, (B) 2-acetamido-4-O-(2-acetamido-3,4,6-trio-O-acetyl-2-deoxy-beta-D-glucopyranosyl)-3,6-di-O-acetyl-2-deoxy-beta-D-glucopyranose (N,N'-diacetylchitobiose pentaacetate), (C) 4-O-(2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl)-2,3,6-trio-O-acetyl-beta-D-glucopyranose (cellobiose heptaacetate); 8-carboxyoctyl glycosides of (D) cellobiose, and (E) N,N'-diacetylchitobiose. Conjugates were prepared from (A), (B), and (C) by coupling to bovine serum albumin by cyanuric trichloride and subsequent deacetylation; (D) and (E) were coupled to bovine serum albumin by the mixed-anhydride reaction. Conjugates (A) and (B) were insoluble; conjugates (C), (D), and (E) functioned as artificial antigens and gave rise to precipitating antibodies in rabbits. Specificities of the antisera were determined by inhibition studies.