Ma Buyuan, Ma Zengxin, Zhang Ning
College of Life Sciences, Qingdao Agricultural University, Qingdao 266109, China; Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China.
College of Life Sciences, Qingdao Agricultural University, Qingdao 266109, China.
Int J Biol Macromol. 2025 Apr;300:140360. doi: 10.1016/j.ijbiomac.2025.140360. Epub 2025 Jan 26.
Metamorphic proteins switch reversibly between distinctly different folds often with different functions under physiological conditions. Here, the kinetics and thermodynamics of the fold-switching at different temperatures in a metamorphic protein, KaiB, involved in cyanobacterial circadian clock, reveal that enthalpy-driven the fold-switching to form fold-switched KaiB (fsKaiB) and the fsKaiB and ground-state KaiB (gsKaiB) are more dominantly at lower and higher temperatures, respectively. Thermodynamic analysis indicates that conformational and solvent entropy have opposing effects on KaiB's fold-switching. The folding kinetic reveals that as KaiB folds, it preferentially folds into gsKaiB and then switches fold to fsKaiB. Temperature-sensitive protein fold-switching can be further extended into applications, such as new temperature-sensitive molecular switcher and biosensors development.
变构蛋白在生理条件下通常会在具有不同功能的截然不同的折叠状态之间可逆地切换。在这里，参与蓝藻生物钟的变构蛋白KaiB在不同温度下折叠转换的动力学和热力学表明，焓驱动折叠转换形成折叠转换态的KaiB（fsKaiB），并且fsKaiB和基态KaiB（gsKaiB）分别在较低和较高温度下占主导地位。热力学分析表明，构象熵和溶剂熵对KaiB的折叠转换具有相反的影响。折叠动力学表明，随着KaiB折叠，它优先折叠成gsKaiB，然后再转换折叠成fsKaiB。对温度敏感的蛋白折叠转换可以进一步扩展到应用中，例如新型温度敏感分子开关和生物传感器的开发。
