Shuji Akiyama／Trans-Hierarchical Molecular Systems
Shuji Akiyama
Professor / CIMoS Director
AKIYAMA, Shuji
Molecular Origin of 24 h Period in Cyanobacterial Protein Clock
KaiC, a core protein of the circadian clock in cyanobacteria, undergoes rhythmic structural changes over approximately 24 h in the presence of KaiA and KaiB (Kai oscillator). This slow dynamics spanning a wide range of both temporal and spatial scales is not well understood, and is central to a fundamental question: what determines the temperature-compensated 24 h period? The Kai oscillator reconstitutable in vitro is advantageous for studying its dynamic structure through a complementary usage of both X-ray crystallography and solution scattering, its transient response by using physicochemical techniques, and its molecular motion through a collaborative work with computational groups. We hope you will join us and enjoy the frontier in molecular science of circadian time-keeping system.
Circadian ticking of cyanobacterial clock protein KaiC (Y. Murayama et al. EMBO J., 30, 68-78 (2011)). The C1 and C2 domains in each protomer of KaiC are drawn as red and blue spheres, respectively. Expansion and contraction motions of the C2 ring (B, C) in solution serves as a timing cue for assembly/disassembly of KaiA and KaiB (D), and is interlocked with its C1 ATPase udder a control of negative-feedback regulation (A).