Changing the net charge from negative to positive makes ribonuclease Sa cytotoxic
Changing the net charge from negative to positive makes ribonuclease Sa cytotoxic
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DOI：
10.1110/ps.0216702
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发表时间：
2002-10-01
期刊：
影响因子：
8
通讯作者：
Makarov, AA
中科院分区：
文献类型：
--
作者：
Ilinskaya, ON;Dreyer, F;Makarov, AA
对来自金黄色链霉菌的核糖核酸酶 Sa (pI = 3.5) 及其 3K (D1K、D17K、E41K) (pI = 6.4) 和 5K (3K + D25K, E74K) (pI = 10.2) 突变体进行了细胞毒性测试。 5K 突变体对正常和 v-ras 转化的 NIH3T3 小鼠成纤维细胞具有细胞毒性，但 RNase Sa 和 3K 则没有。结构。三种蛋白质的稳定性和活性相当，但 pH 7 时的净电荷从 RNase Sa 的 -7 增加到 3K 的 -1 和 5K 的 +3。这些结果表明净正电荷是核糖核酸酶细胞毒性的关键决定因素。细胞毒性 5K 突变体优先攻击 v-ras-NIH3T3 成纤维细胞，表明表达 ras 癌基因的哺乳动物细胞是基于核糖核酸酶的药物的潜在靶标。
Ribonuclease Sa (pI = 3.5) from Streptomyces aureofaciens and its 3K (D1K, D17K, E41K) (pI = 6.4) and 5K (3K + D25K, E74K) (pI = 10.2) mutants were tested for cytotoxicity. The 5K mutant was cytotoxic to normal and v-ras-transformed NIH3T3 mouse fibroblasts, but RNase Sa and 3K were not. The structure. stability, and activity of the three proteins are comparable, but the net charge at pH 7 increases from -7 for RNase Sa to -1 for 3K and to +3 for 5K. These results suggest that a net positive charge is a key determinant of ribonuclease cytotoxicity. The cytotoxic 5K mutant preferentially attacks v-ras-NIH3T3 fibroblasts, suggesting that mammalian cells expressing the ras-oncogene are potential targets for ribonuclease-based drugs.