Facilitated release of substrate protein from prefoldin by chaperonin.
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.
Zako
Tamotsu
T
Department of Physics, School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjyuku-ku, Tokyo 169-8555, Japan. zako@riken.jp
Iizuka
Ryo
R
Okochi
Mina
M
Nomura
Tomoko
T
Ueno
Taro
T
Tadakuma
Hisashi
H
Yohda
Masafumi
M
Funatsu
Takashi
T
D019843:Archaeal Proteins / Q000737:chemistry / Q000378:metabolism*; D018833:Chaperonins / Q000737:chemistry / Q000378:metabolism*; D002950:Citrate (si)-Synthase / Q000737:chemistry; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism*; D043902:Pyrococcus horikoshii / Q000378:metabolism*; D013379:Substrate Specificity
D019843:Archaeal Proteins; D018832:Molecular Chaperones; C112806:prefoldin; D002950:Citrate (si)-Synthase; D018833:Chaperonins