NMR analysis of partially folded states and persistent structure in the alpha subunit of tryptophan synthase: implications for the equilibrium folding mechanism of a 29-kDa TIM barrel protein.
NMR analysis of partially folded states and persistent structure in the alpha subunit of tryptophan synthase: implications for the equilibrium folding mechanism of a 29-kDa TIM barrel protein.
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色氨酸合酶 α 亚基的部分折叠状态和持久结构的 NMR 分析：对 29-kDa TIM 桶状蛋白平衡折叠机制的影响。
DOI：
10.1016/j.jmb.2007.11.010
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发表时间：
2008
影响因子：
5.6
通讯作者：
Matthews,CRobert
中科院分区：
文献类型：
--
作者：
Vadrevu,Ramakrishna;Wu,Ying;Matthews,CRobert
利用互补核磁共振（NMR）技术对大肠杆菌（βα）8TIM桶状蛋白色氨酸合成酶(αTS) α亚基的平衡折叠机制进行了结构分析。通过对主链酰胺氢的天然态氢交换核磁共振分析，探讨了稀有高能部分折叠态的二级结构。对几种15n标记的非极性氨基酸进行二维异核单量子相干核磁共振分析，以探测参与稳定高度变性中间体的侧链，该中间体缺乏二级结构。异亮氨酸和亮氨酸侧链的一个子集的动态展宽和交换保护的缺失表明，自由能图上的最高能量折叠态是由缺乏稳定二级结构的疏水团簇稳定的。这个团簇的核心位于αTS的n端附近，在一个边缘稳定的中间体中起到稳定非天然二级结构的作用。从这个核向几个β链的末端和从n端到c端交换的保护逐渐减少，最好用弱耦合构象的集合来描述。与先前的数据比较强烈地表明，这个集合对应于在折叠的最初几毫秒出现并在平衡条件下持续存在的边缘稳定的非通路中间体。第二种更稳定的中间体，它有一个完整的β-桶和一个磨损的α-螺旋壳，与这个勉强稳定的物种共存。较稳定的中间体向αTS天然态的转化需要形成稳定的螺旋壳，完成三级结构的获得。
Structural insights into the equilibrium folding mechanism of the alpha subunit of tryptophan synthase (αTS) from Escherichia coli, a (βα)8TIM barrel protein, were obtained with a pair of complementary nuclear magnetic resonance (NMR) spectroscopic techniques. The secondary structures of rare high-energy partially folded states were probed by native-state hydrogen-exchange NMR analysis of main-chain amide hydrogens. 2D heteronuclear single quantum coherence NMR analysis of several15N-labeled nonpolar amino acids was used to probe the side chains involved in stabilizing a highly denatured intermediate that is devoid of secondary structure. The dynamic broadening of a subset of isoleucine and leucine side chains and the absence of protection against exchange showed that the highest energy folded state on the free-energy landscape is stabilized by a hydrophobic cluster lacking stable secondary structure. The core of this cluster, centered near the N-terminus of αTS, serves as a nucleus for the stabilization of what appears to be nonnative secondary structure in a marginally stable intermediate. The progressive decrease in protection against exchange from this nucleus toward both termini and from the N-termini to the C-termini of several β-strands is best described by an ensemble of weakly coupled conformers. Comparison with previous data strongly suggests that this ensemble corresponds to a marginally stable off-pathway intermediate that arises in the first few milliseconds of folding and persists under equilibrium conditions. A second, more stable intermediate, which has an intact β-barrel and a frayed α-helical shell, coexists with this marginally stable species. The conversion of the more stable intermediate to the native state of αTS entails the formation of a stable helical shell and completes the acquisition of the tertiary structure.
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蛋白质折叠反应中的障碍。
DOI：
10.1016/s0065-3233(00)53004-6
发表时间：
2000
期刊：
Advances in protein chemistry.
影响因子：
--
作者：
Bilsel,O;Matthews,CR
通讯作者：
Matthews,CR
具体结构出现在色氨酸合酶（一种 TIM 桶状蛋白）α 亚基的亚毫秒折叠中间体的 N 末端。
DOI：
10.1016/j.jmb.2005.06.006
发表时间：
2005
期刊：
Journal of molecular biology.
影响因子：
--
作者：
Wu,Ying;Vadrevu,Ramakrishna;Yang,Xiaoyan;Matthews,CRobert
通讯作者：
Matthews,CRobert
表面环对于稳定八倍 βα 桶蛋白的重要性
影响因子：
8
作者：
R. Urfer;K. Kirschner
通讯作者：
K. Kirschner
通过 NMR 天然态氢交换检查冷休克蛋白 a 的微观稳定性作为尿素和三甲胺 N-氧化物的函数
影响因子：
8
作者：
V. Jaravine;K. Rathgeb‐Szabo;A. Alexandrescu
通讯作者：
A. Alexandrescu
影响因子：
5.6
作者：
Forsyth, William R.;Bilsel, Osman;Matthews, C. Robert
通讯作者：
Matthews, C. Robert