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Proton transfer pathways in bacteriorhodopsin at 2.3 angstrom resolution
H Luecke1, H T Richter, J K Lanyi
1Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA. HUDEL@UCI.EDU
Science (New York, N.Y.)
|June 25, 1998
Summary
Bacteriorhodopsin
Area of Science:
- Structural biology
- Biophysics
- Membrane protein research
Background:
- Bacteriorhodopsin is a light-driven proton pump.
- Its photoisomerization initiates proton translocation across membranes.
- Understanding its mechanism is key to ion pump function.
Purpose of the Study:
- To refine the atomic structure of bacteriorhodopsin.
- To resolve contradictory mechanistic models.
- To elucidate the proton transfer pathway.
Main Methods:
- X-ray diffraction of bacteriorhodopsin crystals grown in cubic lipid phase.
- Structure refinement to 2.3 angstroms, accounting for merohedral twinning.
- Analysis of the active site and surrounding residue network.
Main Results:
- A refined 2.3 angstroms structure of bacteriorhodopsin.
- Identified a hydrogen-bonded water network involving Asp85 and the retinal Schiff base.
- Revealed a proton transfer pathway centered around Arg82 and ordered water molecules.
Conclusions:
- The refined structure provides a new model for bacteriorhodopsin's mechanism.
- The identified network highlights the role of water and residues in proton translocation.
- This work advances the understanding of proton pumps.
Keywords:
Non-programmatic