Biochemistry Publications
Document Type
Article
Publication Date
11-28-2008
Journal
The Journal of biological chemistry
Volume
283
Issue
48
First Page
33602
Last Page
33610
URL with Digital Object Identifier
doi: 10.1074/jbc.M805170200
Abstract
The position of the a subunit of the membrane-integral F0 sector of Escherichia coli ATP synthase was investigated by single molecule fluorescence resonance energy transfer studies utilizing a fusion of enhanced green fluorescent protein to the C terminus of the a subunit and fluorescent labels attached to specific positions of the epsilon or gamma subunits. Three fluorescence resonance energy transfer levels were observed during rotation driven by ATP hydrolysis corresponding to the three resting positions of the rotor subunits, gamma or epsilon, relative to the a subunit of the stator. Comparison of these positions of the rotor sites with those previously determined relative to the b subunit dimer indicates the position of a as adjacent to the b dimer on its counterclockwise side when the enzyme is viewed from the cytoplasm. This relationship provides stability to the membrane interface between a and b2, allowing it to withstand the torque imparted by the rotor during ATP synthesis as well as ATP hydrolysis.
Notes
http://www.jbc.org/content/283/48/33602.full.pdf+html