低分子量GTP结合蛋白公羊p25的Gly19→Val突变体的特性：突变的公羊p25中GTP/GDP结合活性丧失

Characterization of a Gly19-->Val mutant of ram p25, a low Mr GTP-binding protein: loss of GTP/GDP-binding activity in the mutated ram p25.

作者信息

Nagata K, Suzuki T, Okano Y, Hamaguchi M, Nozawa Y

机构信息

Department of Biochemistry, Gifu University School of Medicine, Japan.

出版信息

Biochem Biophys Res Commun. 1992 Nov 30;189(1):330-5. doi: 10.1016/0006-291x(92)91562-5.

DOI:10.1016/0006-291x(92)91562-5

PMID:1449488

Abstract

A substitution of Gly for Val at position 19, which corresponds to oncogenic Gly13-->Val mutation of ras p21, was introduced in a low Mr GTP-binding protein, ram p25. The protein was expressed in cytosolic fraction of Escherichia coli and purified by using specific antibody raised against ram p25. The mutated protein had no guanine nucleotide-binding activity although [Val13]ras p21 was reported to have. The analysis of guanine nucleotide composition of the purified [Val19]ram p25 revealed that the protein was free of nucleotide whereas the normal ram p25 bound about 1 mol of GDP per mol of protein. These results strongly suggested that some part(s) of variable regions as well as the consensus regions are important for the biochemical properties of ram p25.

摘要

在低分子量GTP结合蛋白ram p25中，引入了第19位甘氨酸（Gly）替代缬氨酸（Val）的突变，这与致癌性ras p21的Gly13→Val突变相对应。该蛋白在大肠杆菌的胞质部分表达，并通过使用针对ram p25产生的特异性抗体进行纯化。尽管据报道[Val13]ras p21具有鸟嘌呤核苷酸结合活性，但突变蛋白却没有。对纯化的[Val19]ram p25的鸟嘌呤核苷酸组成分析表明，该蛋白不含核苷酸，而正常的ram p25每摩尔蛋白结合约1摩尔GDP。这些结果有力地表明，可变区以及共有区的某些部分对ram p25的生化特性很重要。