BIOLOGICAL AND BIOCHEMICAL-PROPERTIES OF HUMAN RASH GENES MUTATED AT CODON-61
BIOLOGICAL AND BIOCHEMICAL-PROPERTIES OF HUMAN RASH GENES MUTATED AT CODON-61
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DOI：
10.1016/0092-8674(86)90495-2
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发表时间：
1986-01-01
期刊：
影响因子：
64.5
通讯作者：
COOPER, GM
中科院分区：
文献类型：
--
作者：
DER, CJ;FINKEL, T;COOPER, GM
通过定点诱变，我们在人rasH基因的第61位密码子处引入了编码17种不同氨基酸的突变。其中15种替换增加了rasH的转化活性。剩下的两种突变体，即编码脯氨酸和谷氨酸的突变体，其转化活性与正常基因相似。总体而言，这些突变体在转化能力上的差异超过1000倍。弱转化突变体的转化需要p21表达水平的提高。突变蛋白的鸟嘌呤核苷酸结合特性未发生改变。然而，所有17种不同的突变蛋白都显示出同等程度的GTP水解速率降低，比正常蛋白低8到10倍。GTP酶活性的降低与转化之间没有定量相关性，这表明GTP水解的减少不足以激活ras的转化潜能。
Using site-directed mutagenesis, we have introduced mutations encoding 17 different amino acids at codon 61 of the human rasH gene. Fifteen of these substitutions increased rasH transforming activity. The remaining two mutants, encoding profile and glutamic acid, displayed transforming activities similar to the normal gene. Overall, these mutants vary over 1000-fold in transforming potency. Increased levels of p21 expression were required for transformation by weakly transforming mutants. The mutant proteins were unaltered in guanine nucleotide binding properties. However, all 17 different mutant proteins displayed equivalently reduced rates of GTP hydrolysis, 8- to 10-fold lower than the normal protein. There was no quantitative correlation between reduction in GTPase activity and transformation, indicating that reduced GTP hydrolysis is not sufficient to activate ras transforming potential.