PT  - JOURNAL ARTICLE
AU  - Roh, Soung-Hun
AU  - Shekhar, Mrinal
AU  - Pintilie, Grigore
AU  - Chipot, Christophe
AU  - Wilkens, Stephan
AU  - Singharoy, Abhishek
AU  - Chiu, Wah
TI  - Cryo-EM and MD infer water-mediated proton transport and autoinhibition mechanisms of V<sub>o</sub> complex
AID  - 10.1126/sciadv.abb9605
DP  - 2020 Oct 01
TA  - Science Advances
PG  - eabb9605
VI  - 6
IP  - 41
4099  - http://advances.sciencemag.org/content/6/41/eabb9605.short
4100  - http://advances.sciencemag.org/content/6/41/eabb9605.full
SO  - Sci Adv2020 Oct 01; 6
AB  - Rotary vacuolar adenosine triphosphatases (V-ATPases) drive transmembrane proton transport through a Vo proton channel subcomplex. Despite recent high-resolution structures of several rotary ATPases, the dynamic mechanism of proton pumping remains elusive. Here, we determined a 2.7-Å cryo–electron microscopy (cryo-EM) structure of yeast Vo proton channel in nanodisc that reveals the location of ordered water molecules along the proton path, details of specific protein-lipid interactions, and the architecture of the membrane scaffold protein. Moreover, we uncover a state of Vo that shows the c-ring rotated by ~14°. Molecular dynamics simulations demonstrate that the two rotary states are in thermal equilibrium and depict how the protonation state of essential glutamic acid residues couples water-mediated proton transfer with c-ring rotation. Our cryo-EM models and simulations also rationalize a mechanism for inhibition of passive proton transport as observed for free Vo that is generated as a result of V-ATPase regulation by reversible disassembly in vivo.