Giampapa C S, Abraham S N, Chiang T M, Beachey E H
Department of Microbiology, University of Tennessee, Memphis.
J Biol Chem. 1988 Apr 15;263(11):5362-7.
The adhesion of Escherichia coli to eukaryotic cells is mediated by proteinaceous surface appendages called fimbriae and complementary receptors on host cells. Although type 1 fimbriae, which contain a D-mannose-reactive lectin, have been well studied little is known about the binding mechanism of isolated fimbriae to individual cell receptors. This report describes the isolation and purification of a guinea pig erythrocyte receptor for type 1 fimbriae. Erythrocyte membranes were dissolved in 0.5% Triton X-100 and the receptor isolated and purified by affinity chromatography using type 1 fimbriae immobilized on Sepharose. The 65-kDa receptor, which inhibits the agglutination of guinea pig erythrocytes by type 1 fimbriated E. coli, has a pI of 8.5-8.7, and binds concanavalin A and type 1 fimbriae in a dose-dependent and saturable manner. The fimbrial binding activity of the receptor was reduced when treated with sodium metaperiodate, endoglycosidase H, trypsin, and V8 protease, suggesting the isolated receptor is a glycoprotein with N-linked carbohydrate units. Isolated type 1 fimbriae inhibited the binding of fimbriated E. coli to purified receptor in a dose- and time-related fashion. The calculated binding affinity was 6 X 10(6) M-1, a value consistent with the low binding affinity expected from previous studies of the agglutination of guinea pig erythrocytes by isolated type 1 fimbriae.
大肠杆菌与真核细胞的黏附是由称为菌毛的蛋白质表面附属物和宿主细胞上的互补受体介导的。虽然含有D-甘露糖反应性凝集素的1型菌毛已得到充分研究，但对于分离的菌毛与单个细胞受体的结合机制知之甚少。本报告描述了1型菌毛豚鼠红细胞受体的分离和纯化。红细胞膜溶解于0.5% Triton X-100中，通过使用固定在琼脂糖上的1型菌毛进行亲和层析分离和纯化受体。该65 kDa的受体可抑制1型菌毛化大肠杆菌对豚鼠红细胞的凝集，其pI为8.5 - 8.7，并以剂量依赖性和饱和性方式结合伴刀豆球蛋白A和1型菌毛。用偏高碘酸钠、内切糖苷酶H、胰蛋白酶和V8蛋白酶处理后，该受体的菌毛结合活性降低，提示分离的受体是一种具有N-连接碳水化合物单元的糖蛋白。分离的1型菌毛以剂量和时间相关的方式抑制菌毛化大肠杆菌与纯化受体的结合。计算得到的结合亲和力为6×10⁶ M⁻¹，该值与先前关于分离的1型菌毛对豚鼠红细胞凝集的研究预期的低结合亲和力一致。
