Catalysis-enhancement via rotary fluctuation of f1-atpase

Rikiya Watanabe, Kumiko Hayashi, Hiroshi Ueno, Hiroyuki Noji

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

Protein conformational fluctuations modulate the catalytic powers of enzymes. The frequency of conformational fluctuations may modulate the catalytic rate at individual reaction steps. In this study, we modulated the rotary fluctuation frequency of F1-ATPase (F1) by attaching probes with different viscous drag coefficients at the rotary shaft of F 1. Individual rotation pauses of F1 between rotary steps correspond to the waiting state of a certain elementary reaction step of ATP hydrolysis. This allows us to investigate the impact of the frequency modulation of the rotary fluctuation on the rate of the individual reaction steps by measuring the duration of rotation pauses. Although phosphate release was significantly decelerated, the ATP-binding and hydrolysis steps were less sensitive or insensitive to the viscous drag coefficient of the probe. Brownian dynamics simulation based on a model similar to the Sumi-Marcus theory reproduced the experimental results, providing a theoretical framework for the role of rotational fluctuation in F1 rate enhancement.

Original languageEnglish
Pages (from-to)2385-2391
Number of pages7
JournalBiophysical Journal
Volume105
Issue number10
DOIs
Publication statusPublished - 2013 Nov 19

ASJC Scopus subject areas

  • Biophysics

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