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 m...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.展开更多
α-catenin is an adhesion protein located at the cadherin-based cell-cell adherens junction.α-catenin cross-linksβ-catenin and actin fiber in the adhesion protein complex,and plays an important role in the formation...α-catenin is an adhesion protein located at the cadherin-based cell-cell adherens junction.α-catenin cross-linksβ-catenin and actin fiber in the adhesion protein complex,and plays an important role in the formation and modulation of cell-cell adhesion.The central modulation domains can be unfolded to expose binding site of vinculin when stretching force is applied.Here,we studied the force-induced unfolding dynamics ofα-catenin modulation domains under different loading rates from which the unfolding distance of M2 and M3 domains is determined to be 5-7 nm,and an unfolding intermediate state is identified.We also found that the folding process of M1-M3 domains goes through different pathways with cooperativity.展开更多
基金the National Natural Science Foundation of China(Grant Nos.11874309 and 11474237)the 111 Project(Grant No.B16029)。
文摘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.
基金the National Nature Science Foundation of China(Grant Nos.11474237 and 11574310)the 111 Project(Grant No.B16029).
文摘α-catenin is an adhesion protein located at the cadherin-based cell-cell adherens junction.α-catenin cross-linksβ-catenin and actin fiber in the adhesion protein complex,and plays an important role in the formation and modulation of cell-cell adhesion.The central modulation domains can be unfolded to expose binding site of vinculin when stretching force is applied.Here,we studied the force-induced unfolding dynamics ofα-catenin modulation domains under different loading rates from which the unfolding distance of M2 and M3 domains is determined to be 5-7 nm,and an unfolding intermediate state is identified.We also found that the folding process of M1-M3 domains goes through different pathways with cooperativity.