The molecular chaperone Ssb from Saccharomyces cerevisiae is a component of the ribosome nascent chain complex
The molecular chaperone Ssb from Saccharomyces cerevisiae is a component of the ribosome nascent chain complex
复制标题
DOI：
10.1093/emboj/17.14.3981
复制
发表时间：
1998-07-15
期刊：
影响因子：
11.4
通讯作者：
Craig, EA
中科院分区：
文献类型：
--
作者：
Pfund, C;Lopez-Hoyo, N;Craig, EA
70 kDa热休克蛋白（Hsp70s）是一类普遍存在的分子伴侣蛋白。酿酒酵母的Ssbs是一种丰富的与核糖体翻译相关的Hsp70类型，为了更好地了解Ssb与核糖体相关的功能，对Ssb与核糖体的相互作用进行了表征。通过翻译核糖体掺入氨基trna类似物嘌呤霉素引起Ssb的释放与新生链的释放同时发生。此外，Ssb可以通过光激活交联剂与含有修饰赖氨酸残基的新生链交联。总之，这些结果表明Ssb与新生链的相互作用。Ssb与核糖体-新生链复合物的相互作用是稳定的，对高盐处理的抗性证明了这一点；然而，在缺乏新生链的情况下，Ssb与核糖体的相互作用对盐敏感。我们提出Ssb是翻译核糖体的核心成分，它与新生多肽链和核糖体相互作用，这些相互作用使Ssb作为核糖体上的伴侣，防止新合成的蛋白质错误折叠。
The 70 kDa heat shock proteins (Hsp70s) are a ubiquitous class of molecular chaperones. The Ssbs of Saccharomyces cerevisiae are an abundant type of Hsp70 found associated with translating ribosomes, To understand better the function of Ssb in association with ribosomes, the Ssb-ribosome interaction was characterized. Incorporation of the aminoacyl-tRNA analog puromycin by translating ribosomes caused the release of Ssb concomitant with the release of nascent chains. In addition, Ssb could be cross-linked to nascent chains containing a modified lysine residue with a photoactivatable cross-linker. Together, these results suggest an interaction of Ssb with the nascent chain. The interaction of Ssb with the ribosome-nascent chain complex was stable, as demonstrated by resistance to treatment with high salt; however, Ssb interaction with the ribosome in the absence of nascent chain was salt sensitive. We propose that Ssb is a core component of the translating ribosome which interacts with both the nascent polypeptide chain and the ribosome, These interactions allow Ssb to function as a chaperone on the ribosome, preventing the misfolding of newly synthesized proteins.