Polypeptide flux through bacterial Hsp70: DnaK cooperates with trigger factor in chaperoning nascent chains
Polypeptide flux through bacterial Hsp70: DnaK cooperates with trigger factor in chaperoning nascent chains
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DOI：
10.1016/s0092-8674(00)80787-4
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发表时间：
1999-06-11
期刊：
影响因子：
64.5
通讯作者：
Hartl, FU
中科院分区：
文献类型：
--
作者：
Teter, SA;Houry, WA;Hartl, FU
DnaK，主要的E。coliHsp70中的蛋白质分子伴侣从头折叠仍然是难以捉摸的。在这里，我们表明，在非应激条件下，DnaK瞬时与各种各样的新生和新合成的多肽，与大于30 kDa的链的偏好。缺失非必需基因编码的触发因子，核糖体相关的伴侣，结果在与DnaK相互作用的新生多肽的分数加倍。在正常生长条件下，触发因子和DnaK基因的组合缺失是致命的。这些发现表明DnaK和触发因子在从头蛋白质折叠中具有重要的、部分重叠的功能，并解释了为什么E.杆菌
A role for DnaK, the major E. coli Hsp70, in chaperoning de novo protein folding has remained elusive. Here we show that under nonstress conditions DnaK transiently associates with a wide variety of nascent and newly synthesized polypeptides, with a preference for chains larger than 30 kDa. Deletion of the nonessential gene encoding trigger factor, a ribosome-associated chaperone, results in a doubling of the fraction of nascent polypeptides interacting with DnaK. Combined deletion of the trigger factor and DnaK genes is lethal under normal growth conditions. These findings indicate important, partially overlapping functions of DnaK and trigger factor in de novo protein folding and explain why the loss of either chaperone can be tolerated by E. coli.