Functional profiling of asymmetrically-organized human CCT/TRiC chaperonin.
Molecular organization of the eukaryote chaperonin known as CCT/TRiC complex was recently clarified. Eight distinct subunits are uniquely organized, providing a favorable folding cavity for specific client proteins such as tubulin and actin. Because of its heterogeneous subunit composition, CCT complex has polarized inner faces, which may underlie an essential part of its chaperonin function. In this study, we structurally characterized the closed and open states of CCT complex, using molecular dynamics analyses. Our results showed that the inter-subunit interaction energies were asymmetrically distributed and were remodeled during conformational changes of CCT complex. In addition, exploration of redox related characteristics indicated changes in inner surface properties, including electrostatic potential, pKaand exposure of inner cysteine thiol groups, between the closed and open states. Cysteine activation events were experimentally verified by interaction analyses, using tubulin as a model substrate. Our data highlighted the importance of dynamics-based structural profiling of asymmetrically oriented chaperonin function.
Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064, Japan. Electronic address: k-araki@aist.go.jp.
Kazutaka
K
Araki
Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064, Japan; Department of Biosciences, College of Humanities and Sciences, Nihon University, 3-25-40 Sakurajosui Setagaya-Ku, Tokyo 156-8550, Japan.
Atsushi
A
Suenaga
Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064, Japan.
Hidewo
H
Kusano
Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064, Japan.
Riko
R
Tanaka
Robotic Biology Institute, Inc., Tokyo 135-0064, Japan.
Tomohisa
T
Hatta
Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064, Japan; Robotic Biology Institute, Inc., Tokyo 135-0064, Japan.
Tohru
T
Natsume
Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064, Japan. Electronic address: k-fukui@aist.go.jp.
Kazuhiko
K
Fukui
D056404:Chaperonin Containing TCP-1 / Q000737:chemistry / Q000378:metabolism*; D003198:Computer Simulation; D003545:Cysteine / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011485:Protein Binding; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D055672:Static Electricity; D013816:Thermodynamics
D021122:Protein Subunits; D056404:Chaperonin Containing TCP-1; D003545:Cysteine
CCT; Molecular simulation