Determination of atomic charge in protein molecule by electron diffraction

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K15764
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 43040:Biophysics-related
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Takaba Kiyofumi 国立研究開発法人理化学研究所, 放射光科学研究センター, 特別研究員 (80865460)
• Project Period (FY): 2020-04-01 – 2022-03-31
• Keywords: クライオ電子顕微鏡 / 結晶電子回折 / 放射光X線結晶解析 / 生体分子構造解析 / 電荷解析

Outline of Final Research Achievements

Atomic charges in molecules are parameters of importance, characterizing the nature and the function. In this study we aimed to develop a method to visualize the charge distribution on molecules from microcrystals. We performed both electron and X-ray crystallographic analysis for this purpose, with cryo-electron microscopes and X-ray free electron lasers. We experimentally elucidated that electrons are preferred to visualize atomic charges, while X-rays are preferred to decide atomic position and its thermal motion, based on the property of these interaction sources. This will be a guideline to use either or both methods by researchers’ purposes.

Free Research Field

結晶構造化学

Academic Significance and Societal Importance of the Research Achievements

分子内電荷の実験的決定により, 電子レベルでの構造情報に基づいた機能性分子の理解と開発がより進展すると期待できる. これまでは電子構造は主としてシミュレーションによって評価されてきたが, 実験情報との相互検証によってより高い精度での評価が可能になる.　また, 得たい情報に基づいた実験手法の使い分けや複合利用を促すことで, 電子顕微鏡と放射光X線のそれぞれに期待される装置開発の指針を示すことに繋がる.