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Red/Green Color Tuning of Visual Rhodopsins: Electrostatic Theory Provides a Quantitative Explanation
- Source :
- The journal of physical chemistry. B. 122(18)
- Publication Year :
- 2018
-
Abstract
- We present a structure-based theory of the long-wavelength (red/green) color tuning in visual rhodopsins and its application to the analysis of site-directed mutagenesis experiments. Using a combination of electrostatic and molecular-mechanics methods, we explain the measured mutant-minus-wild-type absorption shifts and conclude that the dominant mechanism of the color tuning in these systems is electrostatic pigment-protein coupling. An important element of our analysis is the independent determination of protonation states of titratable residues in the wild type and the mutant protein as well as the self-consistent reoptimization of hydrogen atom positions, which includes the relaxation of the hydrogen bonding network and the reorientation of water molecules. On the basis of this analysis, we propose a "dipole-orientation rule" according to which both the position and the orientation of a polar group introduced in the protein environment determine the direction of the transition energy shift of the retinal chromophore.
- Subjects :
- 0301 basic medicine
Rhodopsin
genetic structures
Static Electricity
Color
Protonation
010402 general chemistry
01 natural sciences
03 medical and health sciences
Static electricity
Materials Chemistry
Molecule
Animals
Amino Acid Sequence
Physical and Theoretical Chemistry
Absorption (electromagnetic radiation)
Physics
Quantitative Biology::Biomolecules
Hydrogen bond
Relaxation (NMR)
Hydrogen atom
0104 chemical sciences
Surfaces, Coatings and Films
Coupling (electronics)
030104 developmental biology
Absorption, Physicochemical
Chemical physics
Mutagenesis, Site-Directed
Cattle
Subjects
Details
- ISSN :
- 15205207
- Volume :
- 122
- Issue :
- 18
- Database :
- OpenAIRE
- Journal :
- The journal of physical chemistry. B
- Accession number :
- edsair.doi.dedup.....0e27c037e33de8d9b2eabf481405c0d8