Parsons N J, Kwaasi A A, Patel P V, Nairn C A, Smith H
Department of Microbiology, University of Birmingham, UK.
J Gen Microbiol. 1986 Dec;132(12):3277-87. doi: 10.1099/00221287-132-12-3277.
A protein of about 20 kDa was extracted by sodium cholate (1%, w/v) from outer membranes of a strain of Neisseria gonorrhoeae, BS4 (agar), which is resistant to killing by human phagocytes. When the protein was purified by repeated fractionation on Sephadex G75, contamination with other outer-membrane proteins and lipopolysaccharide was negligible. The protein contained a full complement of amino acids, with high levels of glutamic acid. Carbohydrate, detected by the anthrone method and by sugar and hexosamine analysis, was present, but at very low levels. There was a significant content of fatty acids (about 5.7% of the protein), indicating a lipoprotein. The 20 kDa lipoprotein: (1) neutralized the ability of antiserum against whole organisms of BS4 (agar) to reduce the resistance of this strain to phagocyte killing; (2) evoked in mice an antiserum which reduced this resistance and immunoblotted only with 20 kDa lipoprotein in the cholate extract of outer membranes; and (3) promoted resistance to intracellular killing of an otherwise phagocyte susceptible gonococcal strain (BSSH). This is strong evidence that it is a determinant of gonococcal resistance to phagocyte killing.
用胆酸钠（1%，w/v）从一株对人吞噬细胞杀伤具有抗性的淋病奈瑟菌BS4（琼脂）的外膜中提取出一种约20 kDa的蛋白质。当通过在Sephadex G75上反复分级分离对该蛋白质进行纯化时，其他外膜蛋白和脂多糖的污染可忽略不计。该蛋白质含有完整的氨基酸成分，谷氨酸含量较高。通过蒽酮法以及糖和己糖胺分析检测到存在碳水化合物，但含量极低。脂肪酸含量显著（约占蛋白质的5.7%），表明是一种脂蛋白。这种20 kDa的脂蛋白：（1）中和了抗BS4（琼脂）全菌抗血清降低该菌株对吞噬细胞杀伤抗性的能力；（2）在小鼠中诱发了一种抗血清，该抗血清降低了这种抗性，并且在外膜胆酸盐提取物中仅与20 kDa脂蛋白发生免疫印迹反应；（3）增强了对原本易被吞噬细胞吞噬的淋球菌菌株（BSSH）细胞内杀伤的抗性。这有力地证明它是淋球菌对吞噬细胞杀伤抗性的一个决定因素。
