Circadian pacemaker of cyanobacteria by clock protein KaiC

2017 Fiscal Year Final Research Report

• Project/Area Number: 24000016
• Research Category: Grant-in-Aid for Specially Promoted Research
• Allocation Type: Single-year Grants
• Review Section: Biological Sciences
• Research Institution: Nagoya University
• Principal Investigator: KONDO Takao 名古屋大学, 大学院理学研究科, 名誉教授 (10124223)
• Co-Investigator(Kenkyū-buntansha): AKIYAMA Shuji 分子科学研究所, 協奏分子システム研究センター, 教授 (50391842)
• Co-Investigator(Renkei-kenkyūsha): KITAYAMA Yoko 名古屋大学, 大学院理学研究科, 講師 (20444367)
• Project Period (FY): 2012 – 2017
• Keywords: シアノバクテリア / KaiC蛋白質 / 概日時計 / ATPase活性制御 / 機械式概日時計モデル / 時間生物学 / 構造生物化学 / 結晶構造解析

Outline of Final Research Achievements

Circadian clock fit metabolisms of living cells with the day-night cycle of the Earth. The basic mechanism of the circadian clock has been assumed to the autoregulation of clock gene expression in the cell. However, three Kai proteins of cyanobacteria generate precise and stable 24 h rhythm by mixing three proteins with ATP in the test tube. In this project, we focused on biochemical and structural analyses of KaiC and its clock mutants to elucidate the timing mechanism installed in the clock protein KaiC. We found that KaiC ticks time by coupling harmonic pacemaker with driver oscillator by the escapement mechanism, which can be found in the mechanical pendulum clock or classical watches. We are proposing the new clock model for circadian clock and surveying similar mechanisms in eukaryotic clock system.

Free Research Field

時間生物学、植物生理学