New publication!

Nat Comm (2020) "Photoswitching mechanism of a fluorescent protein revealed by time-resolved crystallography and transient absorption spectroscopy"

Reversibly switchable fluorescent proteins (RSFPs) serve as markers in advanced fluorescence imaging. Photoswitching from a non-fluorescent off-state to a fluorescent on-state involves trans-to-cis chromophore isomerization and proton transfer. Whereas excited-state events on the ps timescale have been structurally characterized, conformational changes on slower timescales remain elusive. Here we describe the off-to-on photoswitching mechanism in the RSFP rsEGFP2 by using a combination of time-resolved serial crystallography at an X-ray free-electron laser and ns-resolved pump–probe UV-visible spectroscopy. Ten ns after photoexcitation, the crystal structure features a chromophore that isomerized from trans to cis but the surrounding pocket features conformational differences compared to the final on-state. Spectroscopy identifies the chromophore in this ground-state photo-intermediate as being protonated. Deprotonation then occurs on the μs timescale and correlates with a conformational change of the conserved neighbouring histidine. Together with a previous excited-state study, our data allow establishing a detailed mechanism of off-to-on photoswitching in rsEGFP2.

Click to be redirected to the publications page

Featured Posts
Posts à venir
Tenez-vous à jour...
Recent Posts
Archive
Search By Tags

© 2014-2020 Virgile Adam. All rights reserved

  • LinkedIn
  • Twitter
  • Research Gate
  • Publons
  • Scopus
  • HAL
  • ORCID
  • Google Scholar
  • Mendeley
  • Viadeo
  • Pubfacts