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Updated: Jul 15, 2026
10:37
Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Structural changes in bacteriorhodopsin during ion transport at 2 angstrom resolution.
H Luecke1, B Schobert, H T Richter
1Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA. hudel@uci.edu
Science (New York, N.Y.)
|October 9, 1999
Summary
Structural insights into bacteriorhodopsin
Area of Science:
- Biochemistry
- Structural Biology
- Membrane Proteins
Background:
- Bacteriorhodopsin is a light-driven proton pump crucial for cellular energy generation.
- Understanding its mechanism involves analyzing structural changes during the proton translocation cycle.
- Mutant Asp96Asn provides a model to study specific steps in this cycle.
Purpose of the Study:
- To elucidate the structural basis of the M photointermediate in the Asp96Asn bacteriorhodopsin mutant.
- To understand the molecular rearrangements underlying proton release and energy conservation during the photocycle.
Main Methods:
- X-ray crystallography was used to determine the crystal structures.
- High-resolution structures (1.8 and 2.0 angstroms) of the mutant and its M photointermediate were obtained.
- Analysis of density maps revealed atomic-level structural changes.
Main Results:
- The M photointermediate structure reveals proton transfer to Asp85 and release to the exterior.
- Photoisomerization of retinal to 13-cis,15-anti induces significant side-chain displacements.
- Extensive rearrangements in hydrogen-bonded networks and water molecules alter pKa values.
Conclusions:
- The determined structures provide a detailed view of the late M state in bacteriorhodopsin.
- Structural changes explain energy conservation and directional proton translocation.
- This study offers key insights into the mechanism of light-driven proton pumps.
Keywords:
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