Expression, purification and biochemical characterization of the cytoplasmic loop of PomA, a stator component of the Na+ driven flagellar motor

Rei Abe-Yoshizumi, Shiori Kobayashi, Mizuki Gohara, Kokoro Hayashi, Chojiro Kojima, Seiji Kojima, Yuki Sudo, Yasuo Asami, Michio Homma

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Flagellar motors embedded in bacterial membranes are molecular machines powered by specific ion flows. Each motor is composed of a stator and a rotor and the interactions of those components are believed to generate the torque. Na+ influx through the PomA/PomB stator complex of Vibrio alginolyticus is coupled to torque generation and is speculated to trigger structural changes in the cytoplasmic domain of PomA that interacts with a rotor protein in the C-ring, FliG, to drive the rotation. In this study, we tried to overproduce the cytoplasmic loop of PomA (PomA-Loop), but it was insoluble. Thus, we made a fusion protein with a small soluble tag (GB1) which allowed us to express and characterize the recombinant protein. The structure of the PomA-Loop seems to be very elongated or has a loose tertiary structure. When the PomA-Loop protein was produced in E. coli, a slight dominant effect was observed on motility. We conclude that the cytoplasmic loop alone retains a certain function.

Original languageEnglish
Pages (from-to)21-29
Number of pages9
JournalBiophysics (Japan)
Volume9
DOIs
Publication statusPublished - Feb 12 2013
Externally publishedYes

Keywords

  • Bacterial flagellum
  • Ion-driven motor
  • Protein interaction
  • Stator

ASJC Scopus subject areas

  • Biophysics

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