Transmission of structural changes from catalytic site to transport sites in sarcoplasmic reticulum Ca2+-ATPase

2016 Fiscal Year Final Research Report

• Project/Area Number: 26440017
• 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): 2014-04-01 – 2017-03-31
• Keywords: カルシウムポンプ / 筋小胞体 / ATPアーゼ / リン酸化中間体 / 能動輸送 / グリシン / 異性化 / gating

Outline of Final Research Achievements

Ca2+ pump transports Ca2+ at transport sites of membrane domain coupled to ATP hydrolysis at catalytic site of cytoplasmic domain. The structural roles of M2 helix connecting these domains were investigated by use of site-directed mutagenesis. The results indicated that cytoplasmic region (M2c) and membrane region (M2m) of M2 and junctional loop to cytoplasmic domain have specific functions at specific reaction steps, which enable transmission of structural changes between these domains. The functional roles of Gly105 at connecting region of M2c-M2m were investigated by site-directed substitutions. The results indicated that in the phosphorylated-intermediate isomerization Gly105 with its flexibility absorbs distortion of M2 caused by large structural changes at cytoplasmic domain, and that this enables proper Ca2+-gating and coupled transport.

Free Research Field

生物化学