Privalov P L
Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA.
J Mol Biol. 1996 May 24;258(5):707-25. doi: 10.1006/jmbi.1996.0280.
The efficiency of protein folding suggests that this process proceeds through some intermediate states, raising the possibility of experimental observation of incompletely folded states of proteins. However, critical analysis of the observed partly folded stable states of proteins shows that they present either misfolded forms obtained under conditions inappropriate for folding, or partially unfolded states that retain folded the subpart of these molecules. This retained part, which unfolds last and folds first in a unfolding/refolding experiment, has a definite tertiary structure maintained by specific long-range interactions and can be isolated by fragmentation. Therefore, it can be regarded as a definite domain of the protein molecule. Provided the polypeptide chain of a small single domain protein does not become trapped in a misfolded form, its folding proceeds very rapidly, with all intermediates being transient and extremely unstable.
蛋白质折叠的效率表明这一过程是通过一些中间状态进行的，这增加了实验观察蛋白质不完全折叠状态的可能性。然而，对观察到的蛋白质部分折叠稳定状态的批判性分析表明，它们要么是在不适合折叠的条件下获得的错误折叠形式，要么是保留了这些分子折叠亚部分的部分未折叠状态。这个保留的部分在展开/重新折叠实验中最后展开且最先折叠，具有由特定远程相互作用维持的确定三级结构，并且可以通过片段化分离出来。因此，它可以被视为蛋白质分子的一个确定结构域。如果一个小的单结构域蛋白质的多肽链没有被困在错误折叠的形式中，其折叠过程会非常迅速，所有中间体都是短暂且极其不稳定的。
