Zhu Guoqiang, Chen Huaiqing, Choi Byung-Kwon, Del Piero Fabio, Schifferli Dieter M
Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, 19104, USA.
J Biol Chem. 2005 Jun 17;280(24):23057-65. doi: 10.1074/jbc.M503676200. Epub 2005 Apr 19.
The tip adhesin FasG of the 987P fimbriae of enterotoxigenic Escherichia coli mediates two distinct adhesive interactions with brush border molecules of the intestinal epithelial cells of neonatal piglets. First, FasG attaches strongly to sulfatide with hydroxylated fatty acyl chains. This interaction involves lysine 117 and other lysine residues of FasG. Second, FasG recognizes specific intestinal brush border proteins that migrate on a sodium-dodecyl sulfate-polyacrylamide gel like a distinct set of 32-35-kDa proteins, as shown by ligand blotting assays. The protein sequence of high performance liquid chromatography-purified tryptic fragments of the major protein band matched sequences of human and murine histone H1 proteins. Porcine histone H1 proteins isolated from piglet intestinal epithelial cells demonstrated the same SDS-PAGE migration pattern and 987P binding properties as the 987P-specific protein receptors from porcine intestinal brush borders. Binding was dose-dependent and shown to be specific in adhesion inhibition and gel migration shift assays. Moreover, mapping of the histone H1 binding domain suggested that it is located in their lysine-rich C-terminal domains. Histone H1 molecules were visualized on the microvilli of intestinal epithelial cells by immunohistochemistry and electron microscopy. Taken together these results indicated that the intestinal protein receptors for 987P are histone H1 proteins. It is suggested that histones are released into the intestinal lumen by the high turnover of the intestinal epithelium. Their strong cationic properties can explain their association with the negatively charged brush border surfaces. There, the histone H1 molecules stabilize the sulfatide-fimbriae interaction by simultaneously binding to the membrane and to 987P.
产肠毒素大肠杆菌987P菌毛的尖端黏附素FasG介导了与新生仔猪肠上皮细胞刷状缘分子的两种不同黏附相互作用。首先，FasG与具有羟基化脂肪酰链的硫苷脂紧密结合。这种相互作用涉及FasG的赖氨酸117和其他赖氨酸残基。其次，FasG识别特定的肠刷状缘蛋白，如配体印迹分析所示，这些蛋白在十二烷基硫酸钠-聚丙烯酰胺凝胶上迁移时呈现出一组独特的32-35 kDa蛋白。高效液相色谱纯化的主要蛋白条带的胰蛋白酶片段的蛋白质序列与人和小鼠组蛋白H1蛋白的序列匹配。从小猪肠上皮细胞分离的猪组蛋白H1蛋白表现出与猪肠刷状缘的987P特异性蛋白受体相同的SDS-PAGE迁移模式和987P结合特性。结合呈剂量依赖性，并且在黏附抑制和凝胶迁移位移分析中显示具有特异性。此外，组蛋白H1结合域的定位表明它位于其富含赖氨酸的C末端结构域中。通过免疫组织化学和电子显微镜在肠上皮细胞的微绒毛上观察到组蛋白H1分子。综合这些结果表明，987P的肠蛋白受体是组蛋白H1蛋白。有人提出，组蛋白通过肠上皮的高更新率释放到肠腔中。它们强大的阳离子特性可以解释它们与带负电荷的刷状缘表面的结合。在那里，组蛋白H1分子通过同时结合膜和987P来稳定硫苷脂-菌毛的相互作用。
