2wgm | pdb_00002wgm
Complete ion-coordination structure in the rotor ring of Na-dependent F-ATP synthase
Structural highlights
FunctionATPL_ILYTA F(1)F(0) ATP synthase produces ATP from ADP in the presence of a proton or sodium gradient. F-type ATPases consist of two structural domains, F(1) containing the extramembraneous catalytic core and F(0) containing the membrane sodium channel, linked together by a central stalk and a peripheral stalk. During catalysis, ATP synthesis in the catalytic domain of F(1) is coupled via a rotary mechanism of the central stalk subunits to sodium translocation.[HAMAP-Rule:MF_01396] Key component of the F(0) channel; it plays a direct role in translocation across the membrane. A homomeric c-ring of 11 subunits forms the central stalk rotor element with the F(1) delta and epsilon subunits.[HAMAP-Rule:MF_01396] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe membrane-embedded rotors of Na(+)-dependent F-ATP synthases comprise 11 c-subunits that form a ring, with 11 Na(+) binding sites in between adjacent subunits. Following an updated crystallographic analysis of the c-ring from Ilyobacter tartaricus, we report the complete ion-coordination structure of the Na(+) sites. In addition to the four residues previously identified, there exists a fifth ligand, namely, a buried structural water molecule. This water is itself coordinated by Thr67, which, sequence analysis reveals, is the only residue involved in binding that distinguishes Na(+) synthases from H(+)-ATP synthases known to date. Molecular dynamics simulations and free-energy calculations of the c-ring in a lipid membrane lend clear support to the notion that this fifth ligand is a water molecule, and illustrate its influence on the selectivity of the binding sites. Given the evolutionary ascendancy of sodium over proton bioenergetics, this structure uncovers an ancient strategy for selective ion coupling in ATP synthases. Complete ion-coordination structure in the rotor ring of Na+-dependent F-ATP synthases.,Meier T, Krah A, Bond PJ, Pogoryelov D, Diederichs K, Faraldo-Gomez JD J Mol Biol. 2009 Aug 14;391(2):498-507. Epub 2009 Jun 3. PMID:19500592[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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