Conformational landscape of cytochrome c folding studied by microsecond-resolved small-angle x-ray scattering
Conformational landscape of cytochrome c folding studied by microsecond-resolved small-angle x-ray scattering
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DOI：
10.1073/pnas.012458999
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发表时间：
2002-02-05
影响因子：
11.1
通讯作者：
Fujisawa, T
中科院分区：
文献类型：
--
作者：
Akiyama, S;Takahashi, S;Fujisawa, T
为了从紧密性角度研究蛋白质折叠动力学，我们开发了一种连续流混合装置，进行了时间分辨率为160 μ s的小角度x射线散射测量，并表征了细胞色素c （cyt c）两种折叠中间体的旋转半径（R-g）。早期中间体的R-g约为20埃，比酸展开态的R-g约小4埃。后一中间体的R-g接近于18埃，接近熔球态的R-g。考虑到中间产物的α -螺旋含量（f(H)），我们在由R-g和f(H)定义的构象景观上阐明了cyt c的折叠途径。Cyt c折叠的过程是在蛋白质的一个特定区域周围塌陷，然后是二级结构和致密性的合作获得。
To investigate protein folding dynamics in terms of compactness, we developed a continuous-flow mixing device to make small-angle x-ray scattering measurements with the time resolution of 160 mus and characterized the radius of gyration (R-g) of two folding intermediates of cytochrome c (cyt c). The early intermediate possesses approximate to20 Angstrom of R-g, which is smaller by approximate to4 Angstrom than that of the acid-unfolded state. The R-g of the later intermediate is approximate to18 Angstrom, which is close to that of the molten globule state. Considering the alpha-helix content (f(H)) of the intermediates, we clarified the folding pathway of cyt c on the conformational landscape defined by R-g and f(H). Cyt c folding proceeds with a collapse around a specific region of the protein followed by a cooperative acquisition of secondary structures and compactness.