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Updated: Jul 9, 2026
10:03
Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
Published on: June 27, 2014
Structure of the light-driven chloride pump halorhodopsin at 1.8 A resolution
1Department of Membrane Biochemistry, Max-Planck-Institute for Biochemistry, Am Klopferspitz 18a, D-82152 Martinsried bei München, Germany.
Science (New York, N.Y.)
|May 29, 2000
Summary
This study reveals the high-resolution structure of halorhodopsin, an archaeal rhodopsin, detailing its chloride ion transport mechanism. The findings explain how this vital anion pump utilizes light energy for biological membrane transport.
Area of Science:
- Structural Biology
- Biochemistry
- Membrane Protein Function
Background:
- Halorhodopsin is a light-driven chloride pump found in Haloarchaea.
- Understanding its mechanism is crucial for membrane transport research.
Purpose of the Study:
- To determine the high-resolution crystal structure of halorhodopsin.
- To elucidate the mechanism of chloride ion translocation across biological membranes.
Main Methods:
- Crystallization of halorhodopsin in a cubic lipidic phase.
- X-ray structure determination at 1.8 angstrom resolution.
- Energetic calculations for ion binding and transport.
Main Results:
- Revealed halorhodopsin structure as trimers with palmitic acid.
- Identified a chloride ion at the transport site near Lys(242) and the retinal chromophore.
- Demonstrated stabilization of chloride via ion-ion and ion-dipole interactions.
Conclusions:
- The structure provides atomic-level insight into anion transport by halorhodopsin.
- Ion dragging across the protonated Schiff base explains the equivalence of chloride and proton translocation modes.
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