Open AccessEarly-stage dynamics of chloride ion–pumping rhodopsin revealed by a femtosecond X-ray laser
Author(s) -
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,
Mao Liang,
Raymond G. Sierra,
Thomas J Lane,
Liang Zhou,
Uwe Weierstall,
Nadia A. Zatsepin,
Mio Ohki,
J.R.H. Tame,
Sam Yong Park,
John C. H. Spence,
Wenkai Zhang,
Marius Schmidt,
Weontae Lee,
Haiguang Liu
Publication year - 2021
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.2020486118
Subject(s) - rhodopsin , halorhodopsin , femtosecond , isomerization , ion , chemistry , laser , dissociation (chemistry) , flash photolysis , chloride , photochemistry , molecule , ion transporter , retinal , kinetics , optics , membrane , bacteriorhodopsin , physics , biochemistry , organic chemistry , quantum mechanics , reaction rate constant , catalysis
Chloride ion-pumping rhodopsin (ClR) in some marine bacteria utilizes light energy to actively transport Cl - into cells. How the ClR initiates the transport is elusive. Here, we show the dynamics of ion transport observed with time-resolved serial femtosecond (fs) crystallography using the Linac Coherent Light Source. X-ray pulses captured structural changes in ClR upon flash illumination with a 550 nm fs-pumping laser. High-resolution structures for five time points (dark to 100 ps after flashing) reveal complex and coordinated dynamics comprising retinal isomerization, water molecule rearrangement, and conformational changes of various residues. Combining data from time-resolved spectroscopy experiments and molecular dynamics simulations, this study reveals that the chloride ion close to the Schiff base undergoes a dissociation-diffusion process upon light-triggered retinal isomerization.