Structure and function of glycolipozyme MPIase, involved in protein translocation across and integration into membranes

2016 Fiscal Year Final Research Report

• Project/Area Number: 25291009
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Structural biochemistry
• Research Institution: Iwate University
• Principal Investigator: NISHIYAMA Ken-ichi 岩手大学, 農学部, 教授 (80291334)
• Co-Investigator(Renkei-kenkyūsha): SHIMAMOTO Keiko 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, 主幹研究員 (70235638) ; TOKUDA Hajime 盛岡大学, 栄養科学部, 教授 (40125943)
• Research Collaborator: MOSER Michael ; HUBER Maria ; SASAKI Masaru ; SATO Ryo ; ENDO Yuta ; SAWASATO Katsuhiro ; NISHIKAWA Hanako ; SHIMIZU Yuko ; NAKAMURA Shota ; SAIKUDO Mari
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: タンパク質膜挿入 / タンパク質膜透過 / MPIase / 糖脂質酵素 / SecYEG / YidC

Outline of Final Research Achievements

Structure and function of MPIase were investigated. We found that MPIase is involved in protein integration and translocation in vivo as well as in vitro. We also found that MPIase is essential for cell growth. In the reconstitution system, we proved that MPIase is essential for integration of all the substrate membrane proteins tested. Moreover, the functional interaction between MPIase and YidC was unveiled, strongly suggesting that MPIase functions at an initial stage of integration, while YidC functions at a late stage. Furthermore, we demonstrated that MPIase transforms the dimer orientation of SecYEG into an activated structure in which the cycle of SecG inversion can occur, causing the significant stimulation of translocation.

Free Research Field

生化学