Configuration-Dependent Diffusion Dynamics of Downhill and Two-State Protein Folding

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• 作者：Weixin Xu ; Zaizhi Lai ; Ronaldo J. Oliveira ; Vitor B. P. Leite ; Jin Wang
• 刊名：The Journal of Physical Chemistry B
• 出版年：2012
• 出版时间：May 3, 2012
• 年：2012
• 卷：116
• 期：17
• 页码：5152-5159
• 全文大小：397K
• 年卷期：v.116,no.17(May 3, 2012)
• ISSN：1520-5207

文摘

Configuration-dependent diffusion (CDD) is important for protein folding kinetics with small thermodynamic barriers. CDD can be even more crucial in downhill folding without thermodynamic barriers. We explored the CDD of a downhill protein (BBL), and a two-state protein (CI2). The hidden kinetic barriers due to CDD were revealed. The increased 1 k_BT kinetic barrier is in line with experimental value based on other fast folding proteins. Compared to that of CI2, the effective free-energy profile of BBL is found to be significantly influenced by CDD, and the kinetics are totally determined by diffusion. These findings are consistent with both earlier bulk and single-molecule fluorescence measurements. In addition, we found the temperature dependence of CDD. We also found that the ratio of folding transition temperature against optimal kinetic folding temperature can provide both a quantitative measure for the underlying landscape topography and an indicator for the possible appearance of downhill folding. Our study can help for a better understanding of the role of diffusion in protein folding dynamics.