Energy coupling in Sarcoplasmic Reticulum Ca pump; mechanism of transmitting structural changes between catalytic and transport sites

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K07297
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Structural biochemistry
• Research Institution: Asahikawa Medical College
• Principal Investigator: Daiho Takashi 旭川医科大学, 医学部, 准教授 (90207267)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: P型カチオンポンプ / 筋小胞体 / エネルギー共役 / Ca-ATPase / 部位特異的変異 / ヘリックス / 界面活性剤 / 脂質ヘッドグループ

Outline of Final Research Achievements

In order to explore the transmission mechanism of structural changes between the cytoplasmic domains, which contain the catalytic site and transmembrane domain, which contains the Ca transport sites in sarcoplasmic reticulum Ca-pump ATPase. For this purpose, site-directed mutagenesis and kinetical analysis of the mutants were performed. It was shown that structural changes of M2 helix are important for each reaction step. Importance of interactions between pump protein and lipid head-group was also shown. These results give insights into energy coupling mechanism for ATP hydrolysis and Ca transport in the Ca-pump. Furthermore, effect of solubilization with a detergent was explored.

Free Research Field

生化学

Academic Significance and Societal Importance of the Research Achievements

本研究は、P型カチオンポンプの代表メンバーである筋小胞体Caポンプについて、エネルギー共役機構、とくにM2の折れ曲がりなどの構造変化が果たす役割の理解を深めた。この成果は他のP型カチオンポンプの構造と機能の関連にも示唆を与えることが期待される。また、Caポンプの可溶化に適した界面活性剤を探索し、Caポンプ機能に対する可溶化の効果を解析した成果は、カチオンポンプに限らず、広く膜タンパク質研究に応用可能な示唆を与えることが期待される。