Annu Rev Physiol. 2004;66:665-88. doi: 10.1146/annurev.physiol.66.032102.150049.


Fourier transform infrared and Raman spectroscopy, solid-state NMR, and X-ray crystallography have contributed detailed information about the structural changes in the proton transport cycle of the light-driven pump, bacteriorhodopsin. The results over the past few years add up to a step-by-step description of the configurational changes of the photoisomerized retinal, how these changes result in internal proton transfers and the release of a proton to the extracellular surface and uptake on the other side, as well as the conservation and transformation of excess free energy during the cycle.

Publication types

  • Review

MeSH terms

  • Bacteriorhodopsins / chemistry*
  • Bacteriorhodopsins / metabolism*
  • Biological Transport / radiation effects
  • Extracellular Space / metabolism
  • Isomerism
  • Light
  • Molecular Structure
  • Protons
  • Schiff Bases / metabolism


  • Protons
  • Schiff Bases
  • Bacteriorhodopsins