Zako Tamotsu, Iizuka Ryo, Okochi Mina, Nomura Tomoko, Ueno Taro, Tadakuma Hisashi, Yohda Masafumi, Funatsu Takashi
Department of Physics, School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjyuku-ku, Tokyo 169-8555, Japan.
FEBS Lett. 2005 Jul 4;579(17):3718-24. doi: 10.1016/j.febslet.2005.05.061.
Prefoldin is a chaperone that captures a protein-folding intermediate and transfers it to the group II chaperonin for correct folding. However, kinetics of interactions between prefoldin and substrate proteins have not been investigated. In this study, dissociation constants and dissociation rate constants of unfolded proteins with prefoldin were firstly measured using fluorescence microscopy. Our results suggest that binding and release of prefoldin from hyperthermophilic archaea with substrate proteins were in a dynamic equilibrium. Interestingly, the release of substrate proteins from prefoldin was facilitated when chaperonin was present, supporting a handoff mechanism of substrate proteins from prefoldin to the chaperonin.
预折叠蛋白是一种伴侣蛋白，它捕获蛋白质折叠中间体并将其转移到Ⅱ型伴侣蛋白中进行正确折叠。然而，预折叠蛋白与底物蛋白之间相互作用的动力学尚未得到研究。在本研究中，首先使用荧光显微镜测量了未折叠蛋白与预折叠蛋白的解离常数和解离速率常数。我们的结果表明，嗜热古菌的预折叠蛋白与底物蛋白的结合和释放处于动态平衡。有趣的是，当存在伴侣蛋白时，底物蛋白从预折叠蛋白中的释放得到促进，这支持了底物蛋白从预折叠蛋白到伴侣蛋白的交接机制。
