This title appears in the Scientific Report : 2016 

Structure of the light-driven sodium pump KR2 and its implications for optogenetics
Gushchin, Ivan
Shevchenko, Vitaly / Polovinkin, Vitaly / Borshchevskiy, Valentin / Buslaev, Pavel / Bamberg, Ernst / Gordeliy, Valentin (Corresponding author)
Strukturbiochemie ; ICS-6
The FEBS journal, 283 (2016) 7, S. 1232–1238
Oxford [u.a.] Wiley-Blackwell 2016
26535564
10.1111/febs.13585
Journal Article
Functional Macromolecules and Complexes
Please use the identifier: http://dx.doi.org/10.1111/febs.13585 in citations.
A key and common process present in the organisms from all the domains of life is the maintenance of the ion gradient between inside and outside of the cell. The gradient is generated by various active transporters, among which are the light-driven ion pumps of the microbial rhodopsins family. While the proton- and anion-pumping rhodopsins have been known for a long time, the cation (sodium) pumps were described only recently. Following the discovery, high resolution atomic structures of the pump KR2 were determined that revealed the complete ion translocation pathway, including the positions of the characteristic Asn-Asp-Gln (NDQ) residues, unusual ion uptake cavity acting as a selectivity filter and the unique N-terminal α-helix, capping the ion release cavity, as well as unexpected flexibility of the retinal binding pocket. The structures also revealed pentamerization of KR2 and binding of sodium ions at the interface. Finally, based on the structures, the potassium-pumping KR2 variants have been designed, making the findings even more important for optogenetic applications. In this Structural Snapshot, we analyze the implications of the structural findings for understanding of the sodium translocation mechanism and application of the pump and its mutants in optogenetics. This article is protected by copyright. All rights reserved.This article is protected by copyright. All rights reserved.