Yu Su, Lowe Anson W
Stanford University, Department of Medicine and Stanford Digestive Disease Center, Stanford, USA.
BMC Gastroenterol. 2009 Jul 23;9:58. doi: 10.1186/1471-230X-9-58.
GP2 is the major membrane protein present in the pancreatic zymogen granule, and is cleaved and released into the pancreatic duct along with exocrine secretions. The function of GP2 is unknown. GP2's amino acid sequence is most similar to that of uromodulin, which is secreted by the kidney. Recent studies have demonstrated uromodulin binding to bacterial Type 1 fimbria. The fimbriae serve as adhesins to host receptors. The present study examines whether GP2 also shares similar binding properties to bacteria with Type 1 fimbria. Commensal and pathogenic bacteria, including E. coli and Salmonella, express type 1 fimbria.
An in vitro binding assay was used to assay the binding of recombinant GP2 to defined strains of E. coli that differ in their expression of Type 1 fimbria or its subunit protein, FimH. Studies were also performed to determine whether GP2 binding is dependent on the presence of mannose residues, which is a known determinant for FimH binding.
GP2 binds E. coli that express Type 1 fimbria. Binding is dependent on GP2 glycosylation, and specifically the presence of mannose residues.
GP2 binds to Type 1 fimbria, a bacterial adhesin that is commonly expressed by members of the Enterobacteriacae family.
GP2是胰腺酶原颗粒中存在的主要膜蛋白，会随着外分泌分泌物被切割并释放到胰管中。GP2的功能尚不清楚。GP2的氨基酸序列与由肾脏分泌的尿调节蛋白最为相似。最近的研究表明尿调节蛋白与细菌1型菌毛结合。菌毛作为宿主受体的粘附素。本研究探讨GP2是否也与具有1型菌毛的细菌具有相似的结合特性。共生菌和病原菌，包括大肠杆菌和沙门氏菌，都表达1型菌毛。
采用体外结合试验检测重组GP2与1型菌毛或其亚基蛋白FimH表达不同的特定大肠杆菌菌株的结合。还进行了研究以确定GP2结合是否依赖于甘露糖残基的存在，甘露糖残基是FimH结合的已知决定因素。
GP2与表达1型菌毛的大肠杆菌结合。结合依赖于GP2糖基化，特别是甘露糖残基的存在。
GP2与1型菌毛结合，1型菌毛是肠杆菌科成员普遍表达的一种细菌粘附素。
