Tight Chemomechanical Coupling of the F1 Motor Relies on Structural Stability

Mana Tanaka, Tomohiro Kawakami, Tomoaki Okaniwa, Yohei Nakayama, Shoichi Toyabe, Hiroshi Ueno, Eiro Muneyuki

Research output: Contribution to journalArticlepeer-review

Abstract

The F1 motor is a rotating molecular motor that ensures a tight chemomechanical coupling between ATP hydrolysis/synthesis reactions and rotation steps. However, the mechanism underlying this tight coupling remains to be elucidated. In this study, we used electrorotation in single-molecule experiments using an F1 βE190D mutant to demonstrate that the stall torque was significantly smaller than the wild-type F1, indicating a loose coupling of this mutant, despite showing similar stepping torque as the wild-type. Experiments on the ATPase activity after heat treatment and gel filtration of the α3β3-subcomplex revealed the unstable structure of the βE190D mutant. Our results suggest that the tight chemomechanical coupling of the F1 motor relies on the structural stability of F1. We also discuss the difference between the stepping torque and the stall torque.

Original languageEnglish
Pages (from-to)48-54
Number of pages7
JournalBiophysical Journal
Volume119
Issue number1
DOIs
Publication statusPublished - 2020 Jul 7

ASJC Scopus subject areas

  • Biophysics

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