The ''pre-molten globule,'' a new intermediate in protein folding
The ''pre-molten globule,'' a new intermediate in protein folding
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DOI：
10.1023/a:1026397008011
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发表时间：
1997-07-01
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影响因子：
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通讯作者：
Goldberg, ME
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文献类型：
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作者：
Chaffotte, AF;Guijarro, JI;Goldberg, ME
几种蛋白质的体外折叠研究表明，在2-4毫秒内，形成一个大的远紫外椭圆率，但没有酰胺质子保护的瞬态中间体。为了解决这两种方法估计的二级结构含量之间的矛盾，我们表征了色氨酸合成酶β（2）亚基的分离的C-末端片段F2。在beta（2）中，F2与F1的N-末端区域形成三级相互作用。因此，在没有F1的情况下，分离的F2应该保持在早期折叠阶段，没有长程相互作用。我们将证明，孤立的F2折叠成，并保持在一个“状态”，称为前熔融球，这确实对应于一个2至4毫秒的中间。这种浓缩但不紧凑的“状态”对应于快速平衡的构象阵列，包括天然和非天然二级结构。它符合折叠过程的“新观点”。
In vitro folding studies of several proteins revealed the formation, within 2-4 msec, of transient intermediates with a large far-UV ellipticity but no amide proton protection. To solve the contradiction between the secondary structure contents estimated by these two methods, we characterized the isolated C-terminal fragment F2 of the tryptophan synthase beta(2) subunit. In beta(2), F2 forms its tertiary interactions with the F1 N-terminal region. Hence, in the absence of F1, isolated F2 should remain at an early folding stage with no long-range interactions. We shall show that isolated F2 folds into, and remains in, a ''state'' called the pre-molten globule, that indeed corresponds to a 2- to 4-msec intermediate. This condensed, but not compact, ''state'' corresponds to an array of conformations in rapid equilibrium comprising native as well as nonnative secondary structures. It fits the ''new view'' on the folding process.