Probing the folding transition state structure of the villin headpiece subdomain via side chain and backbone mutagenesis.
Probing the folding transition state structure of the villin headpiece subdomain via side chain and backbone mutagenesis.
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DOI：
10.1021/ja901860f
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发表时间：
2009-06-03
影响因子：
15
通讯作者：
Gai F
中科院分区：
文献类型：
--
作者：
Bunagan MR;Gao J;Kelly JW;Gai F
骨干-骨干氢键是天然蛋白质结构的共同特征，但其对折叠的热力学和动力学影响一直存在争议。这反映在当前蛋白质折叠模型之间的差异上，这些模型将氢键形成置于折叠轨迹的不同阶段。例如，先前的研究表明，绒毛头部亚域的变性状态包含残留的螺旋结构，这可能通过限制与其折叠相关的构象搜索而提供对折叠状态的偏见。尽管螺旋氢键明显地稳定了折叠态，但在这里，我们使用酰胺到酯的突变策略表明，螺旋内主氢键的形成在亚结构域的折叠中并不限制速率，从而表明这种氢键不太可能在从变性态到过渡态的过程中形成。另一方面，旋转区域内氢键的消除导致了较慢的折叠速率，这与这些残基参与折叠核形成的假设一致。虽然说明了螺旋-螺旋-螺旋折叠的潜在保守方面，但我们的结果进一步强调了蛋白质超二级结构形成中旋转的内在重要性。
Backbone-backbone hydrogen bonds are a common feature of native protein structures, yet their thermodynamic and kinetic influence on folding has long been debated. This is reflected by the disparity between current protein folding models, which place hydrogen bond formation at different stages along the folding trajectory. For example, previous studies have suggested that the denatured-state of the villin headpiece subdomain contains residual helical structure that may provide a bias toward the folded state by confining the conformational search associated with its folding. Although helical hydrogen bonds clearly stabilize the folded state, here we show, using an amide-to-ester mutation strategy, that the formation of backbone hydrogen bonds within helices is not rate-limiting in the folding of the subdomain, thereby suggesting that such hydrogen bonds are unlikely to be formed en route from the denatured to the transition state. On the other hand, elimination of hydrogen bonds within the turn region elicits a slower folding rate, consistent with the hypothesis that these residues are involved in the formation of a folding nucleus. While illustrating a potentially conserved aspect of helix-turn-helix folding, our results further underscore the inherent importance of turns in protein supersecondary structure formation.
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DOI：
10.1073/pnas.95.17.9897
发表时间：
1998-08-18
影响因子：
11.1
作者：
Duan, Y;Wang, L;Kollman, PA
通讯作者：
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影响因子：
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DOI：
10.1073/pnas.0502495102
发表时间：
2005-05-24
影响因子：
11.1
作者：
Chiu, TK;Kubelka, J;Davies, DR
通讯作者：
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影响因子：
2.9
作者：
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