Multivalent contacts of the Hsp70 Ssb contribute to its architecture on ribosomes and nascent chain interaction.
Multivalent contacts of the Hsp70 Ssb contribute to its architecture on ribosomes and nascent chain interaction.
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DOI：
10.1038/ncomms13695
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发表时间：
2016-12-05
影响因子：
16.6
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中科院分区：
文献类型：
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Hsp 70分子伴侣有助于所有细胞中新合成蛋白质的从头折叠。在酵母中，专门的Hsp 70 Ssb直接与核糖体结合。Ssb向核糖体募集的结构基础和功能模式尚不清楚。在这里，我们提出的核糖体结合的SSB在酿酒酵母的分子细节。这种相互作用是多方面的，涉及辅助分子RAC和Ssb内以正电荷为特征的两个特定区域。Ssb的C-末端介导关键接触，并且第二附着点由底物结合结构域中的KRR基序提供。引人注目的是，Ssb的核糖体结合不是必需的。自主核糖体附着成为必要的，如果RAC是不存在的，这表明一个双模式的Ssb招聘新生链。我们建议，多层核糖体相互作用允许Ssb定位在隧道出口的最佳方向，保证有效的新生多肽相互作用。 蛋白质的正确折叠通常需要分子伴侣的干预，这可以同时发生。在这里，作者鉴定了酵母Ssb（Hsp 70）介导核糖体结合的元件，并提出了一种指导Ssb与新生链有效相互作用的机制。
Hsp70 chaperones assist de novo folding of newly synthesized proteins in all cells. In yeast, the specialized Hsp70 Ssb directly binds to ribosomes. The structural basis and functional mode of recruitment of Ssb to ribosomes is not understood. Here, we present the molecular details underlying ribosome binding of Ssb in Saccharomyces cerevisiae. This interaction is multifaceted, involving the co-chaperone RAC and two specific regions within Ssb characterized by positive charges. The C-terminus of Ssb mediates the key contact and a second attachment point is provided by a KRR-motif in the substrate binding domain. Strikingly, ribosome binding of Ssb is not essential. Autonomous ribosome attachment becomes necessary if RAC is absent, suggesting a dual mode of Ssb recruitment to nascent chains. We propose, that the multilayered ribosomal interaction allows positioning of Ssb in an optimal orientation to the tunnel exit guaranteeing an efficient nascent polypeptide interaction. The correct folding of proteins often requires the intervention molecular chaperones, which can occur co-translationally. Here the authors identify elements of yeast Ssb (Hsp70) that mediate ribosomal binding, and suggest a mechanism that directs efficient interaction of Ssb with the nascent chain.
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影响因子：
5.5
作者：
Hess, Berk;Kutzner, Carsten;Lindahl, Erik
通讯作者：
Lindahl, Erik
影响因子：
56.9
作者：
Hundley, HA;Walter, W;Craig, EA
通讯作者：
Craig, EA
DOI：
10.1073/pnas.0903503106
发表时间：
2009-05-26
影响因子：
11.1
作者：
Bertelsen, Eric B.;Chang, Lyra;Zuiderweg, Erik R. P.
通讯作者：
Zuiderweg, Erik R. P.
影响因子：
4.4
作者：
ESSMANN, U;PERERA, L;PEDERSEN, LG
通讯作者：
PEDERSEN, LG
影响因子：
16.8
作者：
Huang, P;Gautschi, M;Craig, EA
通讯作者：
Craig, EA