Tikkanen K, Haataja S, François-Gerard C, Finne J
Department of Biochemistry and Biotechnology, University of Kuopio, Finland.
J Biol Chem. 1995 Dec 1;270(48):28874-8. doi: 10.1074/jbc.270.48.28874.
Streptococcus suis causes meningitis, sepsis, and other serious infections in newborn and young pigs and in adult humans. The Gal alpha 1-4Gal-binding adhesin of S. suis was purified to homogeneity by ultrasonic treatment, fractional ammonium sulfate precipitation, and preparative polyacrylamide gel electrophoresis. Pigeon ovomucoid, a glycoprotein with Gal alpha 1-4Gal terminals, was used to detect the adhesin by blotting. The purified adhesin appeared as single band of an apparent size of 18 kDa and of a pI of 6.4; no disulfide bridges were present. The amount of adhesin as revealed by pigeon ovomucoid binding correlated with the hemagglutination activity of different S. suis strains. The purified adhesin bound to latex particles induced hemagglutination which was specifically inhibited with the same inhibitors as hemagglutination by the intact bacteria, thus demonstrating that the purified protein was the Gal alpha 1-4Gal-recognizing adhesin of S. suis. Two adhesin variants (PN and PO) with differing Gal alpha 1-4Gal binding specificity had the similar electrophoretic mobilities and the same N-terminal peptide sequences, indicating that they were closely related. This represents the first isolation of an adhesin with well-defined cell surface carbohydrate binding activity from Gram-positive bacteria associated with meningitis.
猪链球菌可导致新生仔猪、幼猪以及成年人类发生脑膜炎、败血症和其他严重感染。通过超声处理、硫酸铵分级沉淀和制备性聚丙烯酰胺凝胶电泳，将猪链球菌的α1-4半乳糖结合黏附素纯化至同质。用具有α1-4半乳糖末端的糖蛋白鸽卵类黏蛋白通过印迹法检测该黏附素。纯化后的黏附素表现为一条表观大小为18 kDa、pI为6.4的单带；不存在二硫键。鸽卵类黏蛋白结合所显示的黏附素量与不同猪链球菌菌株的血凝活性相关。纯化后的黏附素与乳胶颗粒结合可诱导血凝，其被与完整细菌血凝相同的抑制剂特异性抑制，从而证明纯化后的蛋白是猪链球菌的α1-4半乳糖识别黏附素。两种具有不同α1-4半乳糖结合特异性的黏附素变体（PN和PO）具有相似的电泳迁移率和相同的N端肽序列，表明它们密切相关。这是首次从与脑膜炎相关的革兰氏阳性细菌中分离出具有明确细胞表面碳水化合物结合活性的黏附素。
