Journal
NATURE
Volume 583, Issue 7815, Pages 314-+Publisher
NATURE PORTFOLIO
DOI: 10.1038/s41586-020-2307-8
Keywords
-
Categories
Funding
- Swiss National Science Foundation [31003A_141235, 31003A_159558, PZ00P3_174169, 310030_192780, 310030B_173335]
- NCCR:MUST
- German Research Foundation [SFB-1078, SPP-1926, HE 2063/6-1]
- European Union [701646, 701647]
- European Research Council (ERC) under the European Union [678169]
- Lady Davis Trust
- [SFB 1078]
- Swiss National Science Foundation (SNF) [31003A_159558, PZ00P3_174169, 310030B_173335, 31003A_141235, 310030_192780] Funding Source: Swiss National Science Foundation (SNF)
- Marie Curie Actions (MSCA) [701646] Funding Source: Marie Curie Actions (MSCA)
Ask authors/readers for more resources
Light-driven sodium pumps actively transport small cations across cellular membranes(1). These pumps are used by microorganisms to convert light into membrane potential and have become useful optogenetic tools with applications in neuroscience. Although the resting state structures of the prototypical sodium pump Krokinobacter eikastus rhodopsin 2 (KR2) have been solved(2,3), it is unclear how structural alterations overtime allow sodium to be translocated against a concentration gradient. Here, using the Swiss X-ray Free Electron Laser(4), we have collected serial crystallographic data at ten pump-probe delays from femtoseconds to milliseconds. High-resolution structural snapshots throughout the KR2 photocycle show how retinal isomerization is completed on the femtosecond timescale and changes the local structure of the binding pocket in the early nanoseconds. Subsequent rearrangements and deprotonation of the retinal Schiff base open an electrostatic gate in microseconds. Structural and spectroscopic data, in combination with quantum chemical calculations, indicate that a sodium ion bind stransiently close to the retinal within one millisecond. In the last structural intermediate, at 20 milliseconds after activation, we identified a potential second sodium-binding site close to the extracellular exit. These results provide direct molecular insight into the dynamics of active cation transport across biological membranes.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available