SEQUENCE-ANALYSIS OF 3 SINDBIS VIRUS MUTANTS TEMPERATURE-SENSITIVE IN THE CAPSID PROTEIN AUTOPROTEASE
SEQUENCE-ANALYSIS OF 3 SINDBIS VIRUS MUTANTS TEMPERATURE-SENSITIVE IN THE CAPSID PROTEIN AUTOPROTEASE
复制标题
DOI：
10.1073/pnas.82.14.4648
复制
发表时间：
1985-01-01
影响因子：
11.1
通讯作者：
STRAUSS, JH
中科院分区：
文献类型：
--
作者：
HAHN, CS;STRAUSS, EG;STRAUSS, JH
对编码辛德毕斯病毒3种互补C组突变体ts 2、ts 5和ts 13及其回复突变体的结构蛋白的RNA区域制备的c[互补]DNA进行克隆和测序。这些突变体在非允许温度下其结构蛋白的翻译后加工中具有缺陷。突变体与回复突变体和亲本HR病毒株推导的氨基酸序列的比较表明，所有3个突变体在高度保守的衣壳蛋白的COOH-末端的一半中具有单一氨基酸取代，引起温度敏感性。发现TS 2和TS 5具有相同的损伤，因此代表相同突变体的独立分离，而TS 13具有不同的变化。在所有3个突变体中，温度不敏感性的恢复是通过突变的核苷酸恢复到亲本核苷酸，恢复原始氨基酸而发生的。先前假设衣壳蛋白具有在翻译期间从新生多蛋白切割衣壳蛋白的自蛋白水解活性。衣壳蛋白的氨基酸序列与丝氨酸蛋白酶的氨基酸序列的比较导致我们假设辛德毕斯衣壳蛋白的组氨酸-141，天冬氨酸-147和丝氨酸-215形成丝氨酸蛋白酶的催化三联体。这一假设得到以下发现的支持：所有3个温度敏感性病变映射发生在这些残基附近：ts 2和ts 5改变脯氨酸-218丝氨酸和ts 13赖氨酸-138被异亮氨酸取代。
The c[complementary]DNA made to the region of RNA encoding the structural proteins of 3 complementation group C mutants of Sindbis virus, ts2, ts5 and ts13, and of their revertants was cloned and sequenced. These mutants possess defects in the posttranslational processing of their structural proteins at the nonpermissive temperature. Comparison of the deduced amino acid sequences of the mutants with those of the revertants and with the parental HR strain of virus showed all 3 mutants to have single amino acid substitutions in the highly conserved COOH-terminal half of the capsid protein that give rise to temperature sensitivity. ts2 and ts5 were found to have the same lesion and thus represent independent isolations of the same mutant, whereas ts13 possessed a different change. Reversion to temperature insensitivity in all 3 mutants occurred by reversion of the mutated nucleotide to the parental nucleotide, restoring the original amino acid. It was previously postulated that the capsid protein possesses an autoproteolytic activity that cleaves the capsid protein from the nascent polyprotein during translation. Comparison of the amino acid sequence of the capsid protein with that of serine proteases leads us to hypothesize that histidine-141, aspartate-147 and serine-215 of the Sindbis capsid protein form the catalytic triad of a serine protease. This hypothesis is supported by the finding that all 3 temperature-sensitive lesions mapped occur near these residues: ts2 and ts5 change proline-218 to serine and in ts13 lysine-138 was replaced by isoleucine.