Stimmel J B, Deschenes R J, Volker C, Stock J, Clarke S
Department of Chemistry and Biochemistry, University of California, Los Angeles 90024.
Biochemistry. 1990 Oct 16;29(41):9651-9. doi: 10.1021/bi00493a021.
The protein products of yeast and mammalian ras genes are posttranslationally modified to give mature forms that are localized to the inner surface of the plasma membrane. We have previously demonstrated that the mature form of the Saccharomyces cerevisiae RAS2 gene product is methyl esterified at a modified C-terminal cysteine residue. Here we provide evidence that this residue is an S-farnesylcysteine alpha-carboxyl methyl ester. This result establishes common posttranslational modifications for RAS proteins and fungal sex factors. These polypeptides exhibit sequence similarities at their C-termini that appear to be the critical recognition elements for a common set of modification enzymes. In mammalian cells, proteins with analogous C-terminal sequences appear to be prenylated and carboxyl methylated by a similar mechanism.
酵母和哺乳动物ras基因的蛋白质产物经过翻译后修饰，形成定位于质膜内表面的成熟形式。我们之前已经证明，酿酒酵母RAS2基因产物的成熟形式在一个修饰的C端半胱氨酸残基处被甲基酯化。在这里，我们提供证据表明该残基是S-法尼基半胱氨酸α-羧基甲酯。这一结果确立了RAS蛋白和真菌性因子常见的翻译后修饰。这些多肽在其C末端表现出序列相似性，这似乎是一组共同修饰酶的关键识别元件。在哺乳动物细胞中，具有类似C末端序列的蛋白质似乎通过类似的机制进行异戊二烯化和羧基甲基化。
