An easy alpha-glycosylation methodology for the synthesis and stereochemistry of mycoplasma alpha-glycolipid antigens

作者：Nishida Yoshihiro^*; Shingu Yuko; Yuan Mengfei; Fukuda Kazuo; Dohi Hirofumi; Matsuda Sachie; Matsuda Kazuhiro

来源：Beilstein Journal of Organic Chemistry, 2012, 8.

DOI：10.3762/bjoc.8.70

• cytoplasm membrane
• glycolipid antigen
• glycosylation
• mycoplasma
• stereochemistry

Mycoplasma fermentans possesses unique alpha-glycolipid antigens (GGPL-I and GGPL-III) at the cytoplasm membrane, which carry a phosphocholine group at the sugar primary (6-OH) position. This paper describes a practical synthetic pathway to a GGPL- I homologue (C-16:0) and its diastereomer, in which our one-pot alpha-glycosylation method was effectively applied. The synthetic GGPL-I isomers were characterized with H-1 NMR spectroscopy to determine the equilibrium among the three conformers (gg, gt, tg) at the acyclic glycerol moiety. The natural GGPL-I isomer was found to prefer gt ( 54%) and gg ( 39%) conformers around the lipid tail, while adopting all of the three conformers with equal probability around the sugar position. This property was very close to what we have observed with respect to the conformation of phosphatidylcholine ( DPPC), suggesting that the Mycoplasma glycolipids GGPLs may constitute the cytoplasm fluid membrane together with ubiquitous phospholipids, without inducing stereochemical stress.

• 出版日期2012-4-24