Electric Field Effect on trans‐p‐Hydroxybenzylideneimidazolidinone: A DFT Study and Implication to Green Fluorescent Protein

Abstract

In the present study, density function theory (DFT) calculations were carried out regarding the electric field effect on the trans-p-hydroxybenzylideneimidazolidinone (HBDI), which represents the green fluorescent protein (GFP) chromophore. Structures in the absence or presence of electric fields were fully optimized with the CAM-B3LYP functional, and the corresponding absorption properties were obtained by the timedependent DFT method. It was found that electric field parallel to the x-axis (Fx) has the strongest effect on the charge distribution, and, hence the structure and dipole moment, of the ground state. Furthermore, the absorption energy of the neutral and anionic HBDI monomer was significantly affected by Fx.

Photophysical Engineering of Fluorescent Proteins: Accomplishments and Challenges of Physical Chemistry Strategies

“…Theoretical and experimental studies have examined the influence of electric fields and electrostatics on radiative and nonradiative rates. − ,,,, For example, TD-DFT calculations on the isolated GFP chromophore (Figure ) predict that electric fields can change the oscillator strength of an electronic transition and therefore the radiative rate constant. , Park and Rhee performed nonadiabatic molecular dynamics simulations on the GFP chromophore and found that electrostatic effects can outweigh steric factors impeding the twisting of the methine bridge between the phenoxy and imidazolinone rings, suppressing a major pathway for nonradiative relaxation . Drobizhev and co-workers investigated these issues by measuring two-photon absorption cross sections of RFPs .…”

“…Figure 6. Graphical summary of results from a TD-DFT study performed by Kang et al,97 which demonstrates that the oscillator strength and the absorption maxima for the GFP chromophore can be modulated with changes in the electric field.…”

A New Way to Predict the Efficiency of Optical Limiters without Providing an Experiment: Processing of TDDFT Calculations for the Case of Pure Two-Photon Absorption

“…Deviation from linearity is observed at high values of electric fields, which can be associated with an orbital distortion. 30,31 This, in turn, leads to disturbing the distribution of electron clouds involved in orbitals, which results in a higher overlap during electron transitions. 32 For this reason, in simulations, we have a picture similar to multiphoton absorption, which is observed in laser experiments.…”