Hsp26: a temperature-regulated chaperone
Hsp26: a temperature-regulated chaperone
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DOI：
10.1093/emboj/18.23.6744
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发表时间：
1999-12-01
期刊：
影响因子：
11.4
通讯作者：
Buchner, J
中科院分区：
文献类型：
--
作者：
Haslbeck, M;Walke, S;Buchner, J
小热休克蛋白（sHsps）是一个保守的蛋白质家族，在迄今分析的所有生物体中都发现了其成员。一些sHsps已被证明具有伴侣活性并保护蛋白质免受体外不可逆聚集。在这里，我们证明了Hsp26，一种来自酿酒酵母的sHsp，是一种温度调节的分子伴侣。像其他sHsps一样，Hsp26形成大的寡聚复合物，然而，在热冲击温度下，24分子伴侣复合物解离。有趣的是，在不同温度下进行的伴侣分析表明，热休克温度下Hsp26复合物的解离是有效伴侣活性的先决条件。非天然蛋白与解离的Hsp26结合产生大的球状组装体，其结构似乎与原始Hsp26低聚物完全重组，在这种复合物中，每个Hsp26二聚体结合一个底物单体。活性物种和随后的重新结合到一个确定的大型伴侣-底物复合物代表了分子伴侣功能激活的新机制。
Small heat shock proteins (sHsps) are a conserved protein family, with members found in all organisms analysed so far. Several sHsps have been shown to exhibit chaperone activity and protect proteins from irreversible aggregation lit vitro. Here we show that Hsp26, an sHsp from Saccharomyces cerevisiae, is a temperature-regulated molecular chaperone. Like other sHsps, Hsp26 forms large oligomeric complexes, At heat shock temperatures, however, the 24mer chaperone complex dissociates. Interestingly, chaperone assays performed at different temperatures show that the dissociation of the Hsp26 complex at heat shock temperatures is a prerequisite for efficient chaperone activity. Binding of non-native proteins to dissociated Hsp26 produces large globular assemblies with a structure that appears to be completely reorganized relative to the original Hsp26 oligomers, In this complex one monomer of substrate is bound per Hsp26 dimer, The temperature-dependent dissociation of the large storage form of Hsp26 into a smaller, active species and the subsequent re-association to a defined large chaperone-substrate complex represents a novel mechanism for the functional activation of a molecular chaperone.