Nicolaus B, Trincone A, Esposito E, Vaccaro M R, Gambacorta A, De Rosa M
Istituto per la Chimica di Molecole di Interesse Biologico del Consiglio Nazionale delle Ricerche, Napoli, Italy.
Biochem J. 1990 Mar 15;266(3):785-91.
Lipids from the archaebacterium Sulfolobus solfataricus are based on 72-membered macrocyclic tetraethers made up from two C40 diol units differently cyclized and either two glycerol moieties or one glycerol moiety and a unique branched-chain nonitol named calditol (glycerodialkylnonitol tetraethers, GDNTs). To elucidate the biosynthesis of calditol and related tetraethers, labelled precursors, [U-14C,1(3)-3H]glycerol, [U-14C,2-3H]glycerol, D-[1-14C,6-3H]glucose, D-[6-14C,1-3H]glucose, D-[1-14C,2-3H]glucose, D-[1-14C,6-3H]fructose and D-[1-14C]galactose, were fed to S. solfataricus. Without regard to stereochemistry or phosphorylation, incorporation experiments provided evidence that the biosynthesis of calditol occurs via an aldolic condensation between dihydroxyacetone and fructose, through a 2-oxo derivative of calditol as an intermediate. The latter is in turn reduced and then alkylated to yield the GDNTs. The biogenetic origins of both glycerol and C40 isoprenoid moieties of GDNTs are also discussed.
嗜热栖热菌（Sulfolobus solfataricus）的脂质基于由两个不同环化的C40二醇单元以及两个甘油部分或一个甘油部分和一种名为calditol的独特支链壬糖醇（甘油二烷基壬糖醇四醚，GDNTs）组成的72元大环四醚。为了阐明calditol和相关四醚的生物合成，将标记的前体[U-14C,1(3)-3H]甘油、[U-14C,2-3H]甘油、D-[1-14C,6-3H]葡萄糖、D-[6-14C,1-3H]葡萄糖、D-[1-14C,2-3H]葡萄糖、D-[1-14C,6-3H]果糖和D-[1-14C]半乳糖喂给嗜热栖热菌。不考虑立体化学或磷酸化，掺入实验提供了证据，表明calditol的生物合成通过二羟基丙酮和果糖之间的羟醛缩合，以calditol的2-氧代衍生物作为中间体进行。后者依次被还原，然后烷基化以产生GDNTs。还讨论了GDNTs中甘油和C40类异戊二烯部分的生源起源。
