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Updated: Aug 18, 2026

Visualization of ATP Synthase Dimers in Mitochondria by Electron Cryo-tomography
Published on: September 14, 2014
The catalytic transition state in ATP synthase
A E Senior1, J Weber, S Nadanaciva
1Department of Biochemistry and Biophysics, Box 712, University of Rochester Medical Center, Rochester, New York 14642, USA. alan_senior@urmc.rochester.edu
Abstract:
The catalytic transition state of ATP synthase has been characterized and modeled by combined use of (1) Mg-ADP-fluoroaluminate, Mg-ADP-fluoroscandium, and corresponding Mg-IDP-fluorometals as transition-state analogs; (2) fluorescence signals of beta-Trp331 and beta-Trp148 as optical probes to assess formation of the transition state; (3) mutations of critical catalytic residues to determine side-chain ligands required to stabilize the transition state. Rate acceleration by positive catalytic site cooperativity is explained as due to mobility of alpha-Arg376, acting as an "arginine finger" residue, which interacts with nucleotide specifically at the transition state step of catalysis, not with Mg-ATP- or Mg-ADP-bound ground states. We speculate that formation and collapse of the transition state may engender catalytic site alpha/beta subunit-interface conformational movement, which is linked to gamma-subunit rotation.
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