GroEL-GroES cycling: ATP and nonnative polypeptide direct alternation of folding-active rings
GroEL-GroES cycling: ATP and nonnative polypeptide direct alternation of folding-active rings
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DOI：
10.1016/s0092-8674(00)80742-4
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发表时间：
1999-04-30
期刊：
影响因子：
64.5
通讯作者：
Horwich, AL
中科院分区：
文献类型：
--
作者：
Rye, HS;Roseman, AM;Horwich, AL
双环伴侣蛋白GroEL介导由ATP和GroES结合的环的中央腔中的蛋白质折叠，但目前尚不清楚GroEL如何从一个折叠活性复合物循环到下一个。我们观察到，水解ATP的顺式环内必须发生之前，无论是非天然多肽或GroES可以结合到反式环，这是与反式环顶端结构域的重定向。随后，一个新的顺式三元复合物的形成与多肽结合的开放反式环上进行，这刺激ATP依赖性的解离的顺式复合物（20至50倍），然后由GroES结合。这些结果表明，在非天然蛋白质的存在下，GroEL交替其环作为折叠活性的顺式复合物，每个折叠周期仅消耗一轮7个ATP。
The double-ring chaperonin GroEL mediates protein folding in the central cavity of a ring bound by ATP and GroES, but it is unclear how GroEL cycles from one folding-active complex to the next. We observe that hydrolysis of ATP within the cis ring must occur before either nonnative polypeptide or GroES can bind to the trans ring, and this is associated with reorientation of the trans ring apical domains. Subsequently, formation of a new cis-ternary complex proceeds on the open trans ring with polypeptide binding first, which stimulates the ATP-dependent dissociation of the cis complex (by 20- to 50-fold), followed by GroES binding. These results indicate that, in the presence of nonnative protein, GroEL alternates its rings as folding-active cis complexes, expending only one round of seven ATPs per folding cycle.