Impacts of retinal polyene (de)methylation on the photoisomerization mechanism and photon energy storage of rhodopsin

Walczak, Elżbieta; Andruniów, Tadeusz

doi:10.1039/c5cp01939g

Cited by 8 publications

(10 citation statements)

References 86 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Numerous computational investigations of absorption process in rhodopsin's chromophore involve geometry optimization at the DFT level of theory, as the DFT method seems to be more reliable to optimize the ground‐state geometry of RPSBs and RSBs than CASSCF method and much cheaper in terms of cpu time than MP2 method, followed by subsequent CASPT2 single‐point energy calculations . Therefore, there is a need to determine how the quality of the equilibrium geometry may affect the IPEA correction in the CASPT2 computational scheme.…”

Section: Resultsmentioning

confidence: 99%

Is the choice of a standard zeroth‐order hamiltonian in CASPT2 ansatz optimal in calculations of excitation energies in protonated and unprotonated schiff bases of retinal?

2018

Self Cite

View full text Add to dashboard Cite

To account for systematic error of CASPT2 method empirical modification of the zeroth-order Hamiltonian with Ionization Potential-Electron Affinity (IPEA) shift was introduced. The optimized IPEA value (0.25 a.u.), called standard IPEA (S-IPEA), was recommended but due to its unsatisfactory performance in multiple metallic and organic compounds it has been questioned lately as a general parameter working properly for all molecules under CASPT2 study. As we are interested in Schiff bases of retinal, an important question emerging from this conflict of choice, to use or not to use S-IPEA, is whether the introduction of the modified zeroth-order Hamiltonian into CASPT2 ansatz does really improve their energetics. To achieve this goal, we assessed an impact of the IPEA shift value, in a range of 0-0.35 a.u., on vertical excitation energies to low-lying singlet states of two protonated (RPSBs) and two unprotonated (RSBs) Schiff bases of retinal for which experimental data in gas phase are available. In addition, an effect of geometry, basis set, and active space on computed VEEs is also reported. We find, that for these systems, the choice of S-IPEA significantly overestimates both S →S and S →S energies and the best theoretical estimate, in reference to the experimental data, is provided with either unmodified zeroth-order Hamiltonian or small value of the IPEA shift in a range of 0.05-0.15 a.u., depending on active space and basis set size, equilibrium geometry, and character of the excited state. © 2018 Wiley Periodicals, Inc.

show abstract

Section: Resultsmentioning

confidence: 99%

Is the choice of a standard zeroth‐order hamiltonian in CASPT2 ansatz optimal in calculations of excitation energies in protonated and unprotonated schiff bases of retinal?

2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…In the first case, most of the efforts of research were spent into the study of photochemical process in the bovine rhodopsin, which corresponds to the 11-cis to all-trans isomerization of the retinal protonated Schiff base. 88 Walczak and Andruniow 89 analyzed by using the CASPT2//CASSCF/MM hybrid approach the effects of retinal polyene (de)methylation on the photoisomerization mechanism. Garavelli and co-workers 90,91 showed the advantages of transient 2D electronic spectroscopy to track the evolution of the excited states of retinal along the photoisomerization path.…”

Section: E/z Photoisomerizationsmentioning

confidence: 99%

Advances in computational photochemistry and chemiluminescence of biological and nanotechnological molecules

Roca‐Sanjuán¹,

Francés‐Monerris²,

Galván³

et al. 2016

Photochemistry

View full text Add to dashboard Cite

Recent advances (2014-2015) in computational photochemistry and chemiluminescence derive from the development of theory and from the application of state-of-the-art and new methodology to challenging electronic-structure problems. Method developments have mainly focused, first, on the improvement of approximate and cheap methods to provide a better description of non-adiabatic processes, second, on the modification of accurate methods in order to decrease the computation time and, finally, on dynamics approaches able to provide information that can be directly compared with experimental data, such as yields and lifetimes. Applications of the ab initio quantum-chemistry methods have given rise to relevant findings in distinct fields of the excited-state chemistry. We briefly summarise, in this chapter, the achievements on photochemical mechanisms and chemically-induced excited-state phenomena of interest in biology and nanotechnology.

show abstract

“…The photoisomerization of the retinal protonated Schiff base (RPSB) has been profusely studied from both a theoretical − and an experimental − point of view. Studies inside the protein ,,− and in solution ,− have been performed in order to elucidate the role played by the protein in accelerating the cis/trans photoisomerization and increasing its quantum yield.…”

Section: Introductionmentioning

confidence: 99%

“…Additional information about the de-excitation dynamics can been obtained by introducing small structural modifications ,,,, in the RPSB. Recently, Kukura and co-workers , have shown that the addition of a methyl group at the C 10 position (see Figure ) of RPSB accelerates the electronic decay in methanol solution for both the cis and all- trans isomers and results in protein-like photophysics.…”

Section: Introductionmentioning

confidence: 99%

How Methylation Modifies the Photophysics of the Native All-trans-Retinal Protonated Schiff Base: A CASPT2/MD Study in Gas Phase and in Methanol

et al. 2018

View full text Add to dashboard Cite

A comparison between the free-energy surfaces of the all- trans-retinal protonated Schiff base (RPSB) and its 10-methylated derivative in gas phase and methanol solution is performed at CASSCF//CASSCF and CASPT2//CASSCF levels. Solvent effects were included using the average solvent electrostatic potential from molecular dynamics method. This is a QM/MM (quantum mechanics/molecular mechanics) method that makes use of the mean field approximation. It is found that the methyl group bonded to C10 produces noticeable changes in the solution free-energy profile of the S excited state, mainly in the relative stability of the minimum energy conical intersections (MECIs) with respect to the Franck-Condon (FC) point. The conical intersections yielding the 9- cis and 11- cis isomers are stabilized while that yielding the 13- cis isomer is destabilized; in fact, it becomes inaccessible by excitation to S. Furthermore, the planar S minimum is not present in the methylated compound. The solvent notably stabilizes the S excited state at the FC geometry. Therefore, if the S state has an effect on the photoisomerization dynamics, it must be because it permits the RPSB population to branch around the FC point. All these changes combine to speed up the photoisomerization in the 10-methylated compound with respect to the native compound.

show abstract

Impacts of retinal polyene (de)methylation on the photoisomerization mechanism and photon energy storage of rhodopsin

Cited by 8 publications

References 86 publications

Is the choice of a standard zeroth‐order hamiltonian in CASPT2 ansatz optimal in calculations of excitation energies in protonated and unprotonated schiff bases of retinal?

Is the choice of a standard zeroth‐order hamiltonian in CASPT2 ansatz optimal in calculations of excitation energies in protonated and unprotonated schiff bases of retinal?

Advances in computational photochemistry and chemiluminescence of biological and nanotechnological molecules

How Methylation Modifies the Photophysics of the Native All-trans-Retinal Protonated Schiff Base: A CASPT2/MD Study in Gas Phase and in Methanol

Contact Info

Product

Resources

About