Dissecting the functional role of the N-terminal domain of the human small heat shock protein HSPB6.
Dissecting the functional role of the N-terminal domain of the human small heat shock protein HSPB6.
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DOI：
10.1371/journal.pone.0105892
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Weeks SD
中科院分区：
文献类型：
--
作者：
Heirbaut M;Beelen S;Strelkov SV;Weeks SD
HSPB 6是人类小热休克蛋白（sHSP）家族的成员，该家族是一组保守的分子伴侣，其结合部分未折叠的蛋白质并防止它们聚集。在脊椎动物sHSPs中，结构不良的N-末端结构域与分子伴侣活性和高阶寡聚体的形成有关。这两个功能上重要的属性可能在序列水平上交织在一起，使描绘定义它们的区域的尝试变得复杂。与原型α-晶体蛋白不同，人HSPB 6已被证明仅在溶液中形成二聚体，使得单独探索伴侣活性的决定因素更容易。使用系统的和迭代的删除策略，我们已经广泛地调查了这个sHSP的伴侣活性的N-末端结构域的作用。如通过尺寸排阻色谱和小角X-射线散射所确定的，大多数突变体具有与野生型HSPB 6非常相似的二聚体结构。使用三种不同的底物测试了分子伴侣样活性，其中除了完全去除N-末端结构域之外，没有单一的截短显示出活性的完全丧失，这表明存在多个结合解折叠蛋白的位点。有趣的是，我们发现，延伸涵盖残基31至35，这是几乎完全保守的脊椎动物sHSPs，作为一个负调节活性，因为它的删除大大增强了伴侣的能力。进一步的单点突变分析揭示了高度保守的残基Q31和F33之间的相互作用，微调其功能。
HSPB6 is a member of the human small heat shock protein (sHSP) family, a conserved group of molecular chaperones that bind partially unfolded proteins and prevent them from aggregating. In vertebrate sHSPs the poorly structured N-terminal domain has been implicated in both chaperone activity and the formation of higher-order oligomers. These two functionally important properties are likely intertwined at the sequence level, complicating attempts to delineate the regions that define them. Differing from the prototypical α-crystallins human HSPB6 has been shown to only form dimers in solution making it more amendable to explore the determinants of chaperoning activity alone. Using a systematic and iterative deletion strategy, we have extensively investigated the role of the N-terminal domain on the chaperone activity of this sHSP. As determined by size-exclusion chromatography and small-angle X-ray scattering, most mutants had a dimeric structure closely resembling that of wild-type HSPB6. The chaperone-like activity was tested using three different substrates, whereby no single truncation, except for complete removal of the N-terminal domain, showed full loss of activity, pointing to the presence of multiple sites for binding unfolding proteins. Intriguingly, we found that the stretch encompassing residues 31 to 35, which is nearly fully conserved across vertebrate sHSPs, acts as a negative regulator of activity, as its deletion greatly enhanced chaperoning capability. Further single point mutational analysis revealed an interplay between the highly conserved residues Q31 and F33 in fine-tuning its function.
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DOI：
10.1073/pnas.1114477108
发表时间：
2011-11-01
影响因子：
11.1
作者：
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通讯作者：
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DOI：
10.1016/j.bbapap.2007.01.002
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2007-03-01
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DOI：
10.1007/s10969-011-9100-8
发表时间：
2011-07-01
期刊：
Journal of Structural and Functional Genomics
影响因子：
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作者：
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通讯作者：
LaBaer, Joshua
影响因子：
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作者：
Bumagina Z;Gurvits B;Artemova N;Muranov K;Kurganov B
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