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Updated: Aug 8, 2026

Visualization of ATP Synthase Dimers in Mitochondria by Electron Cryo-tomography
Published on: September 14, 2014
Structure and function of subunit a of the ATP synthase of Escherichia coli
Steven B Vik1, Robert R Ishmukhametov
1Department of Biological Sciences, Southern Methodist University, Dallas, Texas 75275-0376, USA. svik@smu.edu
Abstract:
The structure of subunit a of the Escherichia coli ATP synthase has been probed by construction of more than one hundred monocysteine substitutions. Surface labeling with 3-N-maleimidyl-propionyl biocytin (MPB) has defined five transmembrane helices, the orientation of the protein in the membrane, and information about the relative exposure of the loops connecting these helices. Cross-linking studies using TFPAM-3 (N-(4-azido-2,3,5,6-tetrafluorobenzyl)-3-maleimido-propionamide) and benzophenone-4-maleimide have revealed which elements of subunit a are near subunits b and c. Use of a chemical protease reagent, 5-(-bromoacetamido)-1,10-phenanthroline-copper, has indicated that the periplasmic end of transmembrane helix 5 is near that of transmembrane helix 2.
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