3D Structure of F1 Domain of ATP Synthase

CPK Color Scheme
C O N P Mg

On this page, you can see the F1 domain of bovine mitochondrial ATP synthase.
Reset and spin this ATP synthase molecule.

Notice that there are six alternating subunits (three αsubunits colored blue and three β subunits colored purple) in the "head" portion of the F1 domain around a γ subunit (colored gold) that forms part of the rotating central stalk.

There are six nucleotide binding sites, one at each α-β junction. The three β subunits contain the catalytic sites, while the three α subunits contain noncatalytic sites.

Each catalytic site on the β subunits spontaneously and sequentially transforms into one of three conformations that have different ADP and ATP binding affinities: MgADPDP conformation, which binds ADP and Pi), MgATPTP conformation, which has a high binding affinity for ATP), and empty (βE conformation, which has a low binding affinity for ATP). Notice that one β subunit has a MgADP molecule attached, one has a MgATP molecule attached, and one does not have a ligand bound.

With each 120 turn of the central stalk, the α-helical coiled coil of the γ subunit (shown in magenta) touches a β subunit in the βTP conformation and causes it to release its molecule of ATP and assume the βE conformation. Since each β subunit will assume all three conformations in a given rotational cycle, three molecules of ATP are synthesized for each complete 360° turn of the central stalk. ATP synthase has a maximum speed of 700 RPM, so up to 2100 ATP molecules can be produced per minute!

Works Cited

Ackerman SH, Tzagoloff A. 2005. Function, structure, and biogenesis of mitochondrial ATP synthase. Progress in Nucleic Acid Research and Molecular Biology 80: 95-133.

Abrahams JP, Leslie AGW, Lutter R, Walker JE. Bovine mitochondrial F1-ATPase. [Internet]. 2009 Feb 24 [cited 2010 Apr 8]. RCSB Protein Data Bank. Available from: http://www.pdb.org/pdb/explore/explore.do?structureId=1BMF

Nelson DL, Cox MM. 2008. Lehninger principles of biochemistry. 5th ed. New York (NY): W.H. Freeman and Company; p. 723-732.

von Ballmoos C, Wiedenmann A, Dimroth P. 2009. Essentials for ATP synthesis by F1F0 ATP synthases. Annual Review of Biochemistry 78: 649-672.

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