Publication Abstract from PubMed
The proton pore of the F(1)F(o) ATP synthase consists of a ring of c subunits, which rotates, driven by downhill proton diffusion across the membrane. An essential carboxylate side chain in each subunit provides a proton-binding site. In all the structures of c-rings reported to date, these sites are in a closed, ion-locked state. Structures are here presented of the c(10) ring from Saccharomyces cerevisiae determined at pH 8.3, 6.1 and 5.5, at resolutions of 2.0 A, 2.5 A and 2.0 A, respectively. The overall structure of this mitochondrial c-ring is similar to known homologs, except that the essential carboxylate, Glu59, adopts an open extended conformation. Molecular dynamics simulations reveal that opening of the essential carboxylate is a consequence of the amphiphilic nature of the crystallization buffer. We propose that this new structure represents the functionally open form of the c subunit, which facilitates proton loading and release.
Structure of the c(10) ring of the yeast mitochondrial ATP synthase in the open conformation.,Symersky J, Pagadala V, Osowski D, Krah A, Meier T, Faraldo-Gomez JD, Mueller DM Nat Struct Mol Biol. 2012 Apr 15;19(5):485-91. doi: 10.1038/nsmb.2284. PMID:22504883[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
