A diabatic three-state representation of photoisomerization in the green fluorescent protein chromophore

Olsen, Seth and McKenzie, Ross H. (2009) A diabatic three-state representation of photoisomerization in the green fluorescent protein chromophore. Journal of Chemical Physics, 130 18: 184302.1-184302.13.


Author Olsen, Seth
McKenzie, Ross H.
Title A diabatic three-state representation of photoisomerization in the green fluorescent protein chromophore
Journal name Journal of Chemical Physics   Check publisher's open access policy
ISSN 0021-9606
Publication date 2009-05
Year available 2009
Sub-type Article (original research)
DOI 10.1063/1.3121324
Volume 130
Issue 18
Start page 184302.1
End page 184302.13
Total pages 13
Editor Donald Levy
Place of publication United States of America
Publisher American Institute of Physics
Collection year 2010
Language eng
Abstract We give a quantum chemical description of the photoisomerization reaction of green fluorescent protein (GFP) chromophores using a representation over three diabatic states. Photoisomerization leads to nonradiative decay, and competes with fluorescence in these systems. In the protein, this pathway is suppressed, leading to fluorescence. Understanding the electronic states relevant to photoisomerization is a prerequisite to understanding how the protein suppresses it, and preserves the emitting state of the chromophore. We present a solution to the state-averaged complete active space problem, which is spanned at convergence by three fragment-localized orbitals. We generate the diabatic-state representation by block diagonalization transformation of the Hamiltonian calculated for the anionic chromophore model HBDI with multireference, multistate perturbation theory. The diabatic states are charge localized and admit a natural valence-bond interpretation. At planar geometries, the diabatic picture of the optical excitation reduces to the canonical two-state charge-transfer resonance of the anion. Extension to a three-state model is necessary to describe decay via two possible pathways associated with photoisomerization of the (methine) bridge. Parametric Hamiltonians based on the three-state ansatz can be fit directly to data generated using the underlying active space. We provide an illustrative example of such a parametric Hamiltonian.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Article # 184302

Document type: Journal Article
Sub-type: Article (original research)
Collections: Centre for Organic Photonics and Electronics
School of Mathematics and Physics
2010 Higher Education Research Data Collection
 
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