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Crystal structures reveal the molecular basis of ion translocation in sodium/proton antiporters

DOI: 10.1038/nsmb.3164 DOI Help
PMID: 26828964 PMID Help

Authors: Mathieu Coincon (Stockholm University) , Povilas Uzdavinys (Stockholm University) , Emmanuel Nji (Stockholm University) , David L Dotson (Arizona State University) , Iven Winkelmann (Stockholm University) , Saba Abdul Hussein (Stockholm University) , Alexander D Cameron (University of Warwick) , Oliver Beckstein (Arizona State University) , David Drew (Stockholm University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Nature Structural & Molecular Biology

State: Published (Approved)
Published: February 2016

Abstract: To fully understand the transport mechanism of Na+/H+ exchangers, it is necessary to clearly establish the global rearrangements required to facilitate ion translocation. Currently, two different transport models have been proposed. Some reports have suggested that structural isomerization is achieved through large elevator-like rearrangements similar to those seen in the structurally unrelated sodium-coupled glutamate-transporter homolog GltPh. Others have proposed that only small domain movements are required for ion exchange, and a conventional rocking-bundle model has been proposed instead. Here, to resolve these differences, we report atomic-resolution structures of the same Na+/H+ antiporter (NapA from Thermus thermophilus) in both outward- and inward-facing conformations. These data combined with cross-linking, molecular dynamics simulations and isothermal calorimetry suggest that Na+/H+ antiporters provide alternating access to the ion-binding site by using elevator-like structural transitions.

Journal Keywords: Membrane proteins X-ray crystallography

Subject Areas: Biology and Bio-materials

Diamond Offline Facilities: Membrane Protein Laboratory (MPL)
Instruments: I04-Macromolecular Crystallography , I24-Microfocus Macromolecular Crystallography

Added On: 16/02/2016 11:22

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