Elucidation of Mechanisms on Membrane Protein Integration by a Glycolipid Acting Like an Enzyme

2015 Fiscal Year Final Research Report

• Project/Area Number: 25282235
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Biomolecular chemistry
• Research Institution: Suntory Foundation for Life Sciences
• Principal Investigator: SHIMAMOTO Keiko 公益財団法人サントリー生命科学財団, その他部局等, その他 (70235638)
• Co-Investigator(Renkei-kenkyūsha): MIURA Kaoru (Nomura Kaoru) (公益財団法人)サントリー生命科学財団, 生物有機科学研究所, 研究員 (90353515) ; NISHIYAMA Ken-ichi 岩手大学, 農学部, 教授 (80291334) ; MURATA Michio 大阪大学, 大学院理学研究科, 教授 (40183652)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 糖脂質 / 膜挿入 / 膜タンパク質 / 糖鎖合成 / 生体膜

Outline of Final Research Achievements

We previously reported an integration factor in the inner membrane of E. coli, named MPIase (membrane protein integrase) is a glycolipid composed of diacylglycerol and a glycan chain of three acetylated aminosugars linked through pyrophosphate. MPIase is essential for membrane protein integration and acts like an enzyme. In this study, we showed that O-acetyl groups in the glycan and a phosphate group are required for its activity. NMR experiments indicated the interaction between the acetyl groups of MPIase and the substrate peptide. Based on these results, we propose a plausible mode of action, in which a glycan chain of MPIase captures a substrate to prevent aggregation. Moreover, we synthesized a trisaccharide unit of MPIase to reveal a minimum active structure.

Free Research Field

生物有機化学