39 共生菌由来リポオリゴ糖の単離・構造決定及びそのリピド A の合成と機能 (口頭発表の部)

抄録

Lipopolysaccharides (LPS) are the major glycoconjugates in outer membrane of Gram-negative bacteria and act as potent stimulators of innate immunity. The active principle of LPS is lipid A, the terminal moiety of LPS. Alcaligenes sp. have been known as opportunistic pathogens. Kiyono et al. showed that Alcaligenes faecalis inhabit human Peyer’s patches. Because Peyer’s patches play the important role to regulate the gut immunity, it is suggested that A. faecalis be associated with the regulation of the gut immunity. In this study, we isolated LPS from A. faecalis and found that its LPS is lipooligosaccharide (LOS) with short oligosaccharide compared to general LPS. We also identified the chemical structure of LOS and revealed that this LOS is a novel compound consisting of nona-saccharide and multiple fatty acids. Furthermore, we synthesized A. faecalis lipid A from D-glucosamine hydrochloride (2) via key intermediate disaccharide 3. After the acylation of disaccharide intermediate, two phosphate groups were simultaneously introduced into 14, thus 15 was constructed efficiently. All protective groups were removed to accomplish the synthesis of A. faecalis lipid A 1a.