Analysis of intermediate structure in proton pump mechanism of proteorhodopsin

2016 Fiscal Year Final Research Report

• Project/Area Number: 15K18523
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Biophysics
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Hosaka Toshiaki 国立研究開発法人理化学研究所, ライフサイエンス技術基盤研究センター, 研究員 (40462725)
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: ロドプシン / X線結晶構造解析

Outline of Final Research Achievements

Proteorhodopsin (PR) is one of microbial-type rhodopsins such as bacteriorhodopsin (BR) and functions as a light-driven proton pump. PR-bearing bacteria are widely found among microorganisms in the sea and fresh water. In this study, we aimed for structural analysis of these PRs. PRs were prepared and purified from E. coli cell-free synthesis system and crystallized by LCP method. I presented here (1) two types of PR crystal structure that absorb light at 490 nm and 530 nm, (2) radiation damage-free PR structure, and (3) light absorption-mutant structure of PR. In particular, the structure revealed that the interaction of the amino acid and a water molecule which related to light absorption causes structural changes of retinal.
I participated in the structural analysis of BR intermediate at SACLA and also reported structural analysis of light-driven Cl--pumping rhodopsin that is a homolog of PRs.

Free Research Field

生物学、生物科学、生物物理学