Folding nucleus and unfolding dynamics of protein 2GB1  

作　　者：Xuefeng Wei Yanting Wang 韦学锋;王延颋(CAS Key Laboratory of Theoretical Physics,Institute of Theoretical Physics,Chinese Academy of Sciences,Beijing 100190,China;School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]CAS Key Laboratory of Theoretical Physics,Institute of Theoretical Physics,Chinese Academy of Sciences,Beijing 100190,China [2]School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Chinese Physics B》2021年第2期116-120,共5页中国物理B（英文版）

基　　金：Project supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA17010504);the National Natural Science Foundation of China(Grant No.11947302)。

摘　　要：The folding of many small proteins is kinetically a two-state process with one major free-energy barrier to overcome,which can be roughly regarded as the inverse process of unfolding.In this work,we first use a Gaussian network model to predict the folding nucleus corresponding to the major free-energy barrier of protein 2 GB1,and find that the folding nucleus is located in theβ-sheet domain.High-temperature molecular dynamics simulations are then used to investigate the unfolding process of 2 GB1.We draw free-energy surface from unfolding simulations,taking RMSD and contact number as reaction coordinates,which confirms that the folding of 2 GB1 is kinetically a two-state process.The comparison of the contact maps before and after the free energy barrier indicates that the transition from native to non-native structure of the protein is kinetically caused by the destruction of theβ-sheet domain,which manifests that the folding nucleus is indeed located in theβ-sheet domain.Moreover,the constrained MD simulation further confirms that the destruction of the secondary structures does not alter the topology of the protein retained by the folding nucleus.These results provide vital information for upcoming researchers to further understand protein folding in similar systems.

关 键 词：protein folding 2GB1 two-state model folding nucleus 

分 类 号：Q51[生物学—生物化学]