A three-dimensional movie of structural changes in bacteriorhodopsin

Science. 2016 Dec 23;354(6319):1552-1557. doi: 10.1126/science.aah3497.


Bacteriorhodopsin (bR) is a light-driven proton pump and a model membrane transport protein. We used time-resolved serial femtosecond crystallography at an x-ray free electron laser to visualize conformational changes in bR from nanoseconds to milliseconds following photoactivation. An initially twisted retinal chromophore displaces a conserved tryptophan residue of transmembrane helix F on the cytoplasmic side of the protein while dislodging a key water molecule on the extracellular side. The resulting cascade of structural changes throughout the protein shows how motions are choreographed as bR transports protons uphill against a transmembrane concentration gradient.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteriorhodopsins / chemistry*
  • Bacteriorhodopsins / ultrastructure*
  • Crystallography
  • Cytoplasm / chemistry
  • Imaging, Three-Dimensional*
  • Lasers
  • Motion Pictures
  • Protein Conformation, alpha-Helical
  • Protons
  • Retinaldehyde / chemistry
  • Spectrum Analysis


  • Protons
  • Bacteriorhodopsins
  • Retinaldehyde