Evans D J, Evans D G, Engstrand L, Graham D Y
Bacterial Enteropathogens Laboratory, Veterans Affairs Medical Center, Houston, Texas.
Infect Immun. 1992 May;60(5):2125-7. doi: 10.1128/iai.60.5.2125-2127.1992.
Helicobacter pylori urease is an extracellular, cell-bound enzyme with a molecular weight of approximately 600,000 (600K enzyme) comprising six 66K and six 31K subunits. A 62K protein is closely associated with the H. pylori urease, both in crude preparations and after gel filtration; this protein can be removed from the urease by ion-exchange chromatography without inactivating the enzyme. We purified this urease-associated protein and determined its N-terminal amino acid sequence. The sequence is 80% homologous (identical plus conserved amino acid residues) to the Escherichia coli GroEL heat shock protein (HSP), 75% homologous to the human homolog, and 84% homologous to the HSP homolog found in species of Chlamydia. Thus, the 62K urease-associated protein of H. pylori belongs to the HSP60 family of stress proteins known as chaperonins. Evidently this protein, HSP62, participates in the extracellular assembly and/or protection of the urease against inactivation in the hostile environment of the stomach.
幽门螺杆菌脲酶是一种细胞外、与细胞结合的酶，分子量约为600,000（600K酶），由六个66K亚基和六个31K亚基组成。一种62K蛋白在粗制品和凝胶过滤后都与幽门螺杆菌脲酶紧密相关；这种蛋白可以通过离子交换色谱从脲酶中去除，而不会使酶失活。我们纯化了这种与脲酶相关的蛋白，并确定了其N端氨基酸序列。该序列与大肠杆菌GroEL热休克蛋白（HSP）有80%的同源性（相同氨基酸残基加上保守氨基酸残基），与人类同源物有75%的同源性，与衣原体属中发现的HSP同源物有84%的同源性。因此，幽门螺杆菌的62K脲酶相关蛋白属于被称为伴侣蛋白的HSP60应激蛋白家族。显然，这种蛋白，即HSP62，参与了脲酶在胃的恶劣环境中的细胞外组装和/或保护其不被失活。
