The folding pathway of a protein at high resolution from microseconds to seconds
The folding pathway of a protein at high resolution from microseconds to seconds
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DOI：
10.1073/pnas.94.3.826
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发表时间：
1997-02-04
影响因子：
11.1
通讯作者：
Fersht, AR
中科院分区：
文献类型：
--
作者：
Nolting, B;Golbik, R;Fersht, AR
我们已经记录了折叠途径的10-kDa的蛋白barstar从第一个几微秒在分辨率的个别残基从其良好的表征变性状态。NMR显示变性状态在其四个α-螺旋的前两个中具有闪烁的天然样结构。Phi值分析表明，第一个螺旋变得基本上巩固的中间体是在几百微秒内形成的，因为第二个在较小程度上。然后，随着整个结构的巩固，在几百毫秒内形成了一个类似天然的结构。对应于分别含有前两个螺旋和一起作为螺旋-环-螺旋基序的序列的肽片段在有利于折叠的条件下几乎没有螺旋结构。折叠的早期阶段符合aas为较小的胰凝乳蛋白酶抑制剂2提出的成核-缩合模型，胰凝乳蛋白酶抑制剂2是一个单一的结构模块，并通过双态动力学折叠。更大的、多模块的芽孢杆菌RNA酶的多态折叠的早期阶段已经被证明是实验无法实现的。芽孢杆菌RNA酶抑制剂的折叠途径将CI 2和芽孢杆菌RNA酶的折叠途径联系起来，从而给出了统一的折叠方案。
We have documented the folding pathway of the 10-kDa protein barstar from the first few microseconds at the resolution of individual residues from its well characterized denatured state. The denatured state had been shown from NMR to have flickering native-like structure in the first two of its four alpha-helices. Phi-value analysis shows that the first helix becomes substantially consolidated as the intermediate is formed in a few hundred microseconds, as does the second to a lesser extent. A native-like structure then is formed in a few hundred milliseconds as the whole structure consolidates. Peptide fragments corresponding to sequences containing the first two helices separately and together as a helix-loop-helix motif have little helical structure under conditions that favor folding. The early stages of folding fit the nucleation-condensation model that aas proposed for the smaller chymotrypsin inhibitor 2, which is a single module of structure and folds by two-state kinetics. The early stages of the multistate folding of the larger, multimodular, barnase have proved experimentally inaccessible. The folding pathway of barstar links those of CI2 and barnase to give a unified scheme for folding.