Noel D, Nikaido K, Ames G F
Biochemistry. 1979 Sep 18;18(19):4159-65. doi: 10.1021/bi00586a017.
Mutation hisJ5625 has altered the histidine-binding protein J of Salmonella typhimurium such that histidine transport is impaired, even though binding of histidine by the J protein is unimpaired [Kustu, S.G., & Ames, G.F. (1974) J. Biol. Chem. 249, 6976--6983]. We have determined by protein analytical methods that the only effect of this mutation has been the substitution of a cysteine residue for an arginine at a site in the interior of the polypeptide chain. This arginine residue is therefore potentially essential for the transport function of the protein. The mutant protein migrates in sodium dodecyl sulfate-polyacrylamide gel electrophoresis more slowly than the wild type protein, as if its molecular weight were greater by as much as 2000. Since this behavior is apparently due to a single amino acid replacement, a molecular weight difference even between two closely related proteins should not be inferred solely on the basis of sodium dodecyl sulfate gel electrophoresis.
hisJ5625突变改变了鼠伤寒沙门氏菌的组氨酸结合蛋白J，使得组氨酸转运受损，尽管J蛋白与组氨酸的结合未受影响[库斯图，S.G.，& 艾姆斯，G.F.（1974年）《生物化学杂志》249，6976 - 6983]。我们通过蛋白质分析方法确定，该突变的唯一影响是在多肽链内部的一个位点上，一个精氨酸残基被一个半胱氨酸残基取代。因此，这个精氨酸残基可能对该蛋白的转运功能至关重要。突变蛋白在十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳中的迁移速度比野生型蛋白慢，就好像它的分子量比野生型大多达2000。由于这种行为显然是由单个氨基酸替换引起的，所以即使是两个密切相关的蛋白之间的分子量差异，也不应仅仅基于十二烷基硫酸钠凝胶电泳来推断。
