1] Physik-Department E22 and IMETUM, Technische Universität München, München 85748, Germany [2].
Physik-Department E22 and IMETUM, Technische Universität München, München 85748, Germany.
Nat Commun. 2014 Jun 20;5:4192. doi: 10.1038/ncomms5192.
In living organisms, most proteins work in complexes to form multicomponent protein machines. The function of such multicomponent machines is usually addressed by dividing them into a collection of two state systems at equilibrium. Many molecular machines, like Hsp90, work far from equilibrium by utilizing the energy of ATP hydrolysis. In these cases, important information is gained from the observation of the succession of more than two states in a row. We developed a four-colour single-molecule FRET system to observe the succession of states in the heat shock protein 90 (Hsp90) system, consisting of an Hsp90 dimer, the cochaperone p23 and nucleotides. We show that this multicomponent system is a directional ATP-dependent machinery. This reveals a previously undescribed mechanism on how cochaperones can modify Hsp90, namely by strengthening of the coupling between ATP hydrolysis and a kinetic step involved in the Hsp90 system resulting in a stronger directionality.
在活细胞中，大多数蛋白质通过形成多组分蛋白质机器在复合物中发挥作用。这种多组分机器的功能通常通过将它们划分为一组处于平衡状态的两个状态系统来解决。许多分子机器，如 Hsp90，通过利用 ATP 水解的能量在远离平衡的状态下工作。在这些情况下，通过观察连续多个状态的顺序，可以获得重要信息。我们开发了一种四色单分子 FRET 系统来观察热休克蛋白 90（Hsp90）系统中状态的顺序，该系统由 Hsp90 二聚体、共伴侣 p23 和核苷酸组成。我们表明，这个多组分系统是一种定向的 ATP 依赖性机械装置。这揭示了一种以前未知的机制，即共伴侣如何修饰 Hsp90，即通过加强 ATP 水解与 Hsp90 系统中涉及的动力学步骤之间的耦合，从而导致更强的方向性。
