Structural basis for discrimination between multi-drug exporters and lipid floppies

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K22495
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 47:Pharmaceutical sciences and related fields
• Research Institution: Kyoto University
• Principal Investigator: KATO Hiroaki 京都大学, 薬学研究科, 教授 (90204487)
• Project Period (FY): 2019-06-28 – 2021-03-31
• Keywords: 構造生物学 / 多剤耐性 / トランスポーター / 膜タンパク質 / X結晶学

Outline of Final Research Achievements

Transporters that multiply across a lipid bilayer membrane possess floppase activity which catalyzes translocation of phospholipids from inner side of a membrane to the
outer side or exporter activity which plays efflux of substrate to the out of the membrane. Both activities are powered by ATP as energy source and their molecular structures are very similar. Thus, there is a question that these activities are worked by the same mechanism or there is a distinct molecule that possesses floppase or exporter activity. We plan to alter an exporter structure based on a floppase that has the same protein fold. We determined the crystal structure of the altered transporter and measured the ATP hydrolysis activity. The altered exporter showed floppase-like structure and the activity.

Free Research Field

構造生物学分野

Academic Significance and Societal Importance of the Research Achievements

生体膜の脂質のフリップ・フロップ及び膜を介する基質排出は、多様な細胞生物学や分子生物学と関係する現象であり、病理との関係も深い。ただし、エクスポーターとフロッパーゼの違いを見分けるには、生物学的なアプローチでは観察精度に限界があり、両者の捉え方には多様な主張がある。したがって、両者の機能の違いを詳細な結晶構造に基づいて解明した本研究の意義は大きいと言える。