Dipartimento di Scienze Biochimiche "A. Rossi Fanelli," Sapienza Università di Roma, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Rome, Italy.
Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy.
Protein Sci. 2024 Dec;33(12):e5203. doi: 10.1002/pro.5203.
Protein folding and unfolding experiments are interpreted under the assumption of microscopic reversibility, that is, that at equilibrium one process is the reverse of the other. Single-domain proteins illustrate the validity of such an interpretation, although reversibility does not necessarily hold under the different conditions typically used for folding and unfolding experiments. In fact, more complex proteins, which often exhibit irreversible unfolding, are generally considered not amenable to folding kinetics studies. Here, the X11 PDZ1-PDZ2 tandem repeat allows us to reveal the different folding and unfolding pathways at play under different experimental conditions, thus reconciling the apparent contradiction between theory and experiment.
蛋白质折叠和展开实验是在微观可逆性假设下进行解释的，也就是说，在平衡状态下，一个过程是另一个过程的逆过程。单域蛋白质说明了这种解释的有效性，尽管在通常用于折叠和展开实验的不同条件下，可逆性不一定成立。事实上，更复杂的蛋白质，通常表现出不可逆的展开，通常被认为不适合折叠动力学研究。在这里，X11 PDZ1-PDZ2 串联重复序列使我们能够揭示在不同实验条件下发挥作用的不同折叠和展开途径，从而调和理论和实验之间的明显矛盾。
