The structural and functional analysis of the cyacnobacterial circadian clock protein KaiB

2016 Fiscal Year Final Research Report

• Project/Area Number: 15K18492
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Structural biochemistry
• Research Institution: Nagoya City University
• Principal Investigator: TANIYAMA Reiko (村上怜子) 名古屋市立大学, 大学院薬学研究科, その他 (00444365)
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: 生物時計 / 藍色細菌 / 概日リズム / 溶液散乱 / 超分子質量分析

Outline of Final Research Achievements

The circadian clock is an endogenous biological mechanism that generates autonomous daily cycles. The molecular machinery of the cyanobacterial circadian clock consists of three proteins, KaiA, KaiB, and KaiC. The time information is transmitted from KaiC to SasA.
We showed that mass-spectrometric titration data of KaiB-KaiC complex showed that the proteins formed a complex exclusively in a 6:6 stoichiometry and that the inverse contrast-matching technique of small-angle neutron scattering revealed a disk-shaped arrangement of the KaiB subunits on the outer surface of the KaiC ring, suggesting that cooperatively binding KaiB competes with SasA with respect to interaction with KaiC. On the other hand, KaiB enhanced KaiA-KaiC complex formation. These results suggested that the KaiB play the important role in the regulation of Kai protein complex formation.

Free Research Field

生化学