4bem

Publication Abstract from PubMed

All rotary ATPases catalyse the interconversion of ATP and ADP-Pi through a mechanism that is coupled to the transmembrane flow of H(+) or Na(+). Physiologically, however, F/A-type enzymes specialize in ATP synthesis driven by downhill ion diffusion, while eukaryotic V-type ATPases function as ion pumps. To begin to rationalize the molecular basis for this functional differentiation, we solved the crystal structure of the Na(+)-driven membrane rotor of the Acetobacterium woodii ATP synthase, at 2.1 A resolution. Unlike known structures, this rotor ring is a 9:1 heteromer of F- and V-type c-subunits and therefore features a hybrid configuration of ion-binding sites along its circumference. Molecular and kinetic simulations are used to dissect the mechanisms of Na(+) recognition and rotation of this c-ring, and to explain the functional implications of the V-type c-subunit. These structural and mechanistic insights indicate an evolutionary path between synthases and pumps involving adaptations in the rotor ring.

High-resolution structure and mechanism of an F/V-hybrid rotor ring in a Na(+)-coupled ATP synthase.,Matthies D, Zhou W, Klyszejko AL, Anselmi C, Yildiz O, Brandt K, Muller V, Faraldo-Gomez JD, Meier T Nat Commun. 2014 Nov 10;5:5286. doi: 10.1038/ncomms6286. PMID:25381992^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.