KINETIC IMPAIRMENT OF RESTRICTIVE STREPTOMYCIN-RESISTANT RIBOSOMES
KINETIC IMPAIRMENT OF RESTRICTIVE STREPTOMYCIN-RESISTANT RIBOSOMES
复制标题
DOI：
10.1007/bf00328706
复制
发表时间：
1984-01-01
期刊：
影响因子：
--
通讯作者：
KURLAND, CG
中科院分区：
文献类型：
--
作者：
BOHMAN, K;RUUSALA, T;KURLAND, CG
对具有特定核糖体蛋白 S12 的基因 (rpsL) 的 5 个不同突变等位基因的野生型和其他同基因细菌的体内和体外比较，都对高水平的链霉素具有抗性，表明链霉素抗性 (Smr) 表型可分为主要组，限制性和非限制性。限制性细菌的特征是体内无义抑制频率较低，并且其蛋白质合成速率也比野生型慢。非限制性 Smr 细菌在无义抑制频率或翻译速率方面与野生型没有显着差异。在体外观察到一种互补模式，其中来自限制性 Smr 细菌的核糖体翻译聚（U）的错义错误频率显着低于野生型核糖体，并且相对于其底物（即三元复合物）也显示出增加的 Km。这两种效应都与这些限制性核糖体所特有的更具侵略性的校对功能相关。与野生型相比，从非限制性 Smr 细菌中分离的核糖体在体外校对或错义错误方面没有显示出任何重大差异。
Comparisons in vivo and in vitro of wild-type and otherwise isogenic bacteria with 5 different mutant alleles of the gene (rpsL) specifying ribosomal protein S12, all resistant to high levels of streptomycin, show that the streptomycin-resistant (Smr) phenotype can be subdivided into major groups, restrictive and non-restrictive. The restrictive bacteria have a characteristically lower frequency of nonsense suppression in vivo and are also slower than the wild type in their rate of protein synthesis. Non-restrictive Smr bacteria do not differ significantly from the wild type in nonsense suppression frequencies or in the rate of translation. A complementary pattern is seen in vitro, where ribosomes from the restrictive Smr bacteria translate poly(U) with a significantly lower missense error frequency than wild-type ribosomes and also show an increased Km with respect to their substrate, i.e., ternary complexes. Both effects are correlated with the more aggressive proofreading function that is characteristic of these restrictive ribosomes. Ribosomes isolated from the non-restrictive Smr bacteria do not show any major difference in proofreading or missense error in vitro when compared with the wild type.