中国物理B ›› 2021, Vol. 30 ›› Issue (7): 78201-078201.doi: 10.1088/1674-1056/abfb56

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Equilibrium folding and unfolding dynamics to reveal detailed free energy landscape of src SH3 protein by magnetic tweezers

Huanhuan Su(苏环环)1,†, Hao Sun(孙皓)1,†, Haiyan Hong(洪海燕)1, Zilong Guo(郭子龙)2,3, Ping Yu(余平)1, and Hu Chen(陈虎)1,2,3,‡   

  1. 1 Institute for Biomimetics and Soft Matter, Fujian Provincial Key Laboratory for Soft Functional Materials Research, Department of Physics, Xiamen University, Xiamen 361005, China;
    2 Center of Biomedical Physics, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325000, China;
    3 Oujiang Laboratory, Wenzhou 325000, China
  • 收稿日期:2021-03-17 修回日期:2021-04-15 接受日期:2021-04-26 出版日期:2021-06-22 发布日期:2021-06-22
  • 通讯作者: Hu Chen E-mail:chenhu@xmu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11874309 and 11474237) and the 111 Project (Grant No. B16029).

Equilibrium folding and unfolding dynamics to reveal detailed free energy landscape of src SH3 protein by magnetic tweezers

Huanhuan Su(苏环环)1,†, Hao Sun(孙皓)1,†, Haiyan Hong(洪海燕)1, Zilong Guo(郭子龙)2,3, Ping Yu(余平)1, and Hu Chen(陈虎)1,2,3,‡   

  1. 1 Institute for Biomimetics and Soft Matter, Fujian Provincial Key Laboratory for Soft Functional Materials Research, Department of Physics, Xiamen University, Xiamen 361005, China;
    2 Center of Biomedical Physics, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou 325000, China;
    3 Oujiang Laboratory, Wenzhou 325000, China
  • Received:2021-03-17 Revised:2021-04-15 Accepted:2021-04-26 Online:2021-06-22 Published:2021-06-22
  • Contact: Hu Chen E-mail:chenhu@xmu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11874309 and 11474237) and the 111 Project (Grant No. B16029).

摘要: Src SH3 protein domain is a typical two-state protein which has been confirmed by research of denaturant-induced unfolding dynamics. Force spectroscopy experiments by optical tweezers and atomic force microscopy have measured the force-dependent unfolding rates with different kinds of pulling geometry. However, the equilibrium folding and unfolding dynamics at constant forces has not been reported. Here, using stable magnetic tweezers, we performed equilibrium folding and unfolding dynamic measurement and force-jump measurement of src SH3 domain with tethering points at its N- and C-termini. From the obtained force-dependent transition rates, a detailed two-state free energy landscape of src SH3 protein is constructed with quantitative information of folding free energy, transition state barrier height and position, which exemplifies the capability of magnetic tweezers to study protein folding and unfolding dynamics.

关键词: protein folding and unfolding, magnetic tweezers, free energy landscape, transition state

Abstract: Src SH3 protein domain is a typical two-state protein which has been confirmed by research of denaturant-induced unfolding dynamics. Force spectroscopy experiments by optical tweezers and atomic force microscopy have measured the force-dependent unfolding rates with different kinds of pulling geometry. However, the equilibrium folding and unfolding dynamics at constant forces has not been reported. Here, using stable magnetic tweezers, we performed equilibrium folding and unfolding dynamic measurement and force-jump measurement of src SH3 domain with tethering points at its N- and C-termini. From the obtained force-dependent transition rates, a detailed two-state free energy landscape of src SH3 protein is constructed with quantitative information of folding free energy, transition state barrier height and position, which exemplifies the capability of magnetic tweezers to study protein folding and unfolding dynamics.

Key words: protein folding and unfolding, magnetic tweezers, free energy landscape, transition state

中图分类号:  (Single molecule manipulation of proteins and other biological molecules)

  • 82.37.Rs
82.20.Db (Transition state theory and statistical theories of rate constants) 87.15.R- (Reactions and kinetics) 87.14.E- (Proteins)