Early-stage dynamics of chloride ion–pumping rhodopsin revealed by a femtosecond X-ray laser

• DOI: 10.1073/pnas.2020486118
• Publication Date: 2021-03-22T20:25:46Z
• Authors: Ji-Hye Yun; Xuanxuan Li; Jianing Yue; Jae-Hyun Park; Zeyu Jin; Chufeng Li; Hao Hu; Yingchen Shi; Suraj Pandey; Sergio Carbajo; Sébastien Boutet; Mark S. Hunter; Mengning Liang; Raymond G. Sierra; Thomas J. Lane; Liang Zhou; Uwe Weierstall; Nadia A. Zatsepin; Mio Ohki; Jeremy R. H. Tame; Sam-Yong Park; John C. H. Spence; Wenkai Zhang; Marius Schmidt; Weontae Lee; Haiguang Liu
• Keywords: Protein Conformation, alpha-Helical; 0301 basic medicine; Protein Structure; serial femtosecond crystallography; Protein Conformation; Nocardioides; Molecular Dynamics Simulation; 530; Physical Chemistry; Monovalent; 03 medical and health sciences; Microbial; Chlorides; Chloride Channels; Cations; Rhodopsins, Microbial; Rhodopsins; Eye Disease and Disorders of Vision; Uncategorized; Crystallography; light-driven chloride-pumping rhodopsin; Electromagnetic Radiation; Lasers; alpha-Helical; Neurosciences; Water; Biological Sciences; Cations, Monovalent; 540; Recombinant Proteins; Protein Structure, Tertiary; time-resolved crystallography; Chemical Sciences; Retinaldehyde; X-ray free-electron laser; Tertiary

Significance

Light-driven rhodopsin proteins pump ions across cell membranes. They have applications in optogenetics and can potentially be used to develop solar energy–harvesting devices. A detailed understanding of rhodopsin dynamics and functions may therefore assist research in medicine, health, and clean energy. This time-resolved crystallography study carried out with X-ray free-electron lasers reveals detailed dynamics of chloride ion–pumping rhodopsin (ClR) within 100 ps of light activation. It shows the dissociation of Cl − from the Schiff base binding site upon light-triggered retinal isomerization. This Cl − dissociation is followed by diffusion toward the intracellular direction. The results hint at a common ion-pumping mechanism across rhodopsin families.