Molecular mechanism of kinase activation of light sensor protein phototropin

2014 Fiscal Year Final Research Report

• Project/Area Number: 25840047
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Biophysics
• Research Institution: Kyoto University
• Principal Investigator: NAKASONE Yusuke 京都大学, 理学(系)研究科(研究院), 助教 (00613019)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: phototropin / LOVドメイン / 過渡回折格子法 / 蛋白質反応 / 光センサータンパク質

Outline of Final Research Achievements

Phototropins (phots) are blue-light dependent kinases in higher plants as well as in green algae. They contain two LOV domains (LOV1 and LOV2) as light sensing modules. In this study, we investigated the reaction dynamics of full-length phot and its shorter fragments from Chlamydomonas reinhardtii (Cr-phot) to understand the mechanism of kinase activation by the transient grating (TG) method.
We have detected global reactions in milliseconds time scale as a decrease of diffusion coefficient (D). The rate constant of the D change depended on the protein concentration linearly, indicating that the reaction was bimolecular reaction (dimerization). This reaction was mediated by the LOV1 domain and the contribution of the LOV2 domain to the D change was very minor. These findings are different from those of phot from Arabidopsis, which represents the diversity of phot among organisms.

Free Research Field

生体分子科学