脆弱类杆菌NCTC9343内毒素类脂A的结构特征

STRUCTURAL PROPERTIES OF THE LIPID A COMPONENT OF THE LIPOPOLYSACCHARIDE (ENDOTOXIN) ISOLATED FROM BACTERIODES FRAGILIS NCTC 9343

应用化学及液气相色谱技术分析了脆弱类杆菌NCTC 9343内毒素的类脂A成分。实验表明此类脂A基本骨架系由β1’,6-糖苷键相联的D-氨基葡萄糖组成。骨架的C-1位被以α-糖苷键相联的磷酸基团取代,而C-4’位磷酸缺失。脆弱类杆菌类脂A属低度酰化的分子,每一分子仅携带5.2分子脂肪酸(其中形成0.73分子的3-脂酰基脂肪酸)。含有这种不完全酰化类脂A分子的内毒素已被证实表达较低的生物学活性。

Various chemical and gas-liquid chromatographic analyses indicate that the lipid A backbone of the lipopolysaccharide (LPS) isolated from Bacteriodes fragilis NCTC 9343 is chemically constituted by a β1, 6-interlinked D-gluco-samine disaccharide. It is phosphorylated at its 1-position by a glycosidic-linkage while the ester-bound phosphate present generally in other lipid A is depleted. The lipid A is lower fatty acylated in the amount of 5.2 fatty acids per lipid A molecule (of which 0.73 forms 3-acyloxyacyl groups). The LPS containing such a lipid A component has been shown endowing with a weaker endotoxicity.