CHARACTERIZATION OF THE GENE RIMK RESPONSIBLE FOR THE ADDITION OF GLUTAMIC-ACID RESIDUES TO THE C-TERMINUS OF RIBOSOMAL PROTEIN-S6 IN ESCHERICHIA-COLI-K12
CHARACTERIZATION OF THE GENE RIMK RESPONSIBLE FOR THE ADDITION OF GLUTAMIC-ACID RESIDUES TO THE C-TERMINUS OF RIBOSOMAL PROTEIN-S6 IN ESCHERICHIA-COLI-K12
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DOI：
10.1007/bf02464894
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发表时间：
1989-06-01
期刊：
影响因子：
--
通讯作者：
ISONO, K
中科院分区：
文献类型：
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作者：
KANG, WK;ICHO, T;ISONO, K
野生型大肠杆菌菌株的核糖体蛋白 S6 在其 C 末端含有多达 6 个谷氨酸残基。前两个残基由该蛋白质的结构基因 (rpsF) 编码，其余残基在翻译后添加。分离出缺乏这种修饰的突变体，并对其进行遗传和生物化学表征。正如预期的那样，这些突变体中的 S6 蛋白似乎在 C 末端仅包含两个谷氨酸残基。突变基因被称为 rimK，并在 cmlA 和 aroA 之间的 18.7 分钟处定位。将rimK基因克隆到粘粒载体中并测定其核苷酸序列。对该基因的转录和翻译产物的分析表明，它编码Mr为31.5 kDa的蛋白质，并且它与编码24 kDa蛋白质的基因形成操纵子。分离出在蛋白质 S6 C 末端的第二个残基中含有 Glu 至 Lys 替换的 rpsF 突变体。该突变体的 S6 蛋白显然无法进入 RimK 修饰系统。这表明RimK修饰系统至少在核糖体蛋白S6的C端区域需要野生型氨基酸序列。
Ribosomal protein S6 of wild-type strains of Escherichia coli contains up to six glutamic acid residues at its C-terminus. The first two residues are encoded by the structural gene for this protein (rpsF) and the rest are added post-translationally. Mutants deficient in this modification were isolated and characterized genetically and biochemically. The S6 protein in these mutants appeared to contain only two glutamic acid residues at the C-terminus as expected. The mutated gene was termed rimK and was mapped at 18.7 min between cmlA and aroA. The rimK gene was cloned into a cosmid vector and its nucleotide sequence determined. Analysis of the transcriptional and translational products of this gene indicates that it encodes a protein with an Mr of 31.5 kDa and that it forms an operon with a gene encoding a 24 kDa protein. An rpsF mutant containing a Glu to Lys replacement in the second residue from the C-terminus of protein S6 was isolated. The S6 protein of this mutant was apparently inaccessible to the RimK modification system. This indicates that the RimK modification system requires the wild-type amino acid sequence at least in the C-terminal region of ribosomal protein S6.