Electrostatic control of photoisomerization in the photoactive yellow protein chromophore: Ab initio multiple spawning dynamics

Ko, Chaehyuk; Virshup, Aaron M.; Martı́nez, Todd J.

doi:10.1016/j.cplett.2008.05.029

Cited by 56 publications

(72 citation statements)

References 33 publications

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“…A theoretical model involving a single point charge near the phenolate group of an anionic analog of the PYP chromophore, showed that the charge drives the isomerization about the ethylenic bond. 68 Other calculations carried on WT indeed indicated that presence of Arg52, placed sideways with respect to the chromophore, would only induce a moderate stabilization of the S 1 state at the perp geometry. 45 In a preceding letter, 11 we excluded a crucial role of the positive charge borne by Arg52 by experimentally comparing the transient absorption decays of R52Q and WT.…”

Section: Effect Of Local Charge On the Isomerization Processmentioning

confidence: 96%

Structural Effects on the Ultrafast Photoisomerization of Photoactive Yellow Protein. Transient Absorption Spectroscopy of Two Point Mutants

et al. 2009

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Subpicosecond transient absorption spectroscopy was used to address the role of the local environment on the photoisomerization process of the p-coumaric thioester chromophore in photoactive yellow protein (PYP) by studying two point mutants, T50V and E46Q. These mutations introduce alterations of the hydrogen-bond network involving the amino acids of the active site close to the chromophore and the chromophore phenolate group, respectively. Transient-absorption spectra of T50V and E46Q are found to be qualitatively similar to those of the wild-type PYP (WT) and R52Q, suggesting that the earliest steps of the photoinduced processes in all three mutants remain similar to those of the WT. Target analyses of the transient spectra of T50V, E46Q, R52Q, and WT, were successfully performed by using a model based on the one previously published by Larsen et al. (Biophys. J. 2004, 87, 1858, which involves heterogeneous excited-state populations undergoing deactivation along two competitive relaxation pathways. A so-called reactive pathway leads to the sequential formation of the well-characterized cis intermediates, I 0 and I 1 , of the photocycle. The second pathway is non reactive and produces a transient species that restores the initial trans ground-state in 3-6 ps. This transient is tentatively attributed to a distorted vibrationally hot trans ground state. The most prominent effect of mutation is observed for T50V and R52Q which exhibit significantly slower excited-state deactivations, whereas E46Q behaves like the WT protein. This difference is analyzed in terms of a significant decrease, in T50V and R52Q, of the fraction of heterogeneous excited-state population that undergoes isomerization. The quantum yield of isomerization deduced from the target analyses was found to be 0.31 ( 0.08 for WT, 0.22 ( 0.06 for T50V, 0.29 ( 0.08 for E46Q, and 0.19 ( 0.05 for R52Q. The decrease of isomerization yield observed in T50V and R52Q is mainly attributed to the loss of rigidity of the protein active site, induced by these mutations, rather than to the deletion of the positive charge of Arg52 in R52Q.

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Section: Effect Of Local Charge On the Isomerization Processmentioning

confidence: 96%

Structural Effects on the Ultrafast Photoisomerization of Photoactive Yellow Protein. Transient Absorption Spectroscopy of Two Point Mutants

et al. 2009

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“…In the latter case, simulations have suggested that protonation and field effects can influence the driving forces for distinct twisting channels. [124][125][126][127] Experimental studies indicate that titration affects the solvent-dependence of the decay rate. 128 The possibility of charge-transfer deactivation pathways has been noted.…”

Section: A General Discussionmentioning

confidence: 99%

A two-state model of twisted intramolecular charge-transfer in monomethine dyes

Olsen

McKenzie

2012

The Journal of Chemical Physics

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Articles you may be interested inModeling opto-electronic properties of a dye molecule in proximity of a semiconductor nanoparticle J. Chem. Phys. 139, 024105 (2013) A two-state model Hamiltonian is proposed, which can describe the coupling of twisting displacements to charge-transfer behavior in the ground and excited states of a general monomethine dye molecule. This coupling may be relevant to the molecular mechanism of environment-dependent fluorescence yield enhancement. The model is parameterized against quantum chemical calculations on different protonation states of the green fluorescent protein chromophore, which are chosen to sample different regimes of detuning from the cyanine (resonant) limit. The model provides a simple yet realistic description of the charge transfer character along two possible excited state twisting channels associated with the methine bridge. It describes qualitatively different behavior in three regions that can be classified by their relationship to the resonant (cyanine) limit. The regimes differ by the presence or absence of twist-dependent polarization reversal and the occurrence of conical intersections. We find that selective biasing of one twisting channel over another by an applied diabatic biasing potential can only be achieved in a finite range of parameters near the cyanine limit.

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“…31 More recent simulations suggest that this mechanism may control photoisomerization in photoactive yellow protein chromophores. 32 In order to address the importance of charge transfer for preservation of the emitting state, it is necessary to have models that can represent these effects. This is, in principle, possible with "quantum mechanical/molecular mechanical" methods, 33 but these techniques ͑as generally applied͒ are so expensive as to prohibit sufficient sampling.…”

Section: Why Is This State Not Observed In Chromophores Outside Of Thmentioning

confidence: 99%

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

Olsen

McKenzie

2009

The Journal of Chemical Physics

122

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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 non-radiative 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 multi-reference, multi-state 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.

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Electrostatic control of photoisomerization in the photoactive yellow protein chromophore: Ab initio multiple spawning dynamics

Cited by 56 publications

References 33 publications

Structural Effects on the Ultrafast Photoisomerization of Photoactive Yellow Protein. Transient Absorption Spectroscopy of Two Point Mutants

Structural Effects on the Ultrafast Photoisomerization of Photoactive Yellow Protein. Transient Absorption Spectroscopy of Two Point Mutants

A two-state model of twisted intramolecular charge-transfer in monomethine dyes

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

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