Electric field effect on the ground state proton transfer in the H-bonded HBDI complex: an implication of the green fluorescent protein

Abstract

In this paper, first-principles calculations were performed regarding the electric field effect on the ground state proton transfer (GSPT) in the H-bonded p-hydroxybenzylideneimidazolidinone (HBDI) network that represents the active site of the green fluorescent protein (GFP).

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

“…Meanwhile, R C2–C3 and R C3–C4 are 1.404 and 1.390 Å, due to the bonding character (π) of both C2–C3 and C3–C4, as seen from the HOMO. This phenomenon is similar to that in the cis isomers …”

“…The magnitude of equilibrium constant was found to be closely fitted to a linear relationship under the effect of electric fields. The electric field was further revealed to significantly alter the GSPT mechanism, which is concerted and asynchronous in field‐free conditions . Additionally, it was found that the electric field parallel to a specific orientation can significantly affect the photochemical properties .…”

“…Much effort has been made on understanding this issue focusing on only cis isomers as the target. We also performed a theoretical study of field effect on the ground state proton transfer (GSPT) of cis GFP . The magnitude of equilibrium constant was found to be closely fitted to a linear relationship under the effect of electric fields.…”

“…The electric field was further revealed to significantly alter the GSPT mechanism, which is concerted and asynchronous in field‐free conditions . Additionally, it was found that the electric field parallel to a specific orientation can significantly affect the photochemical properties . Since the direction and strength of electric field can be manipulated by controlling the position of charged or polar amino acid residues, the electric field could be a potential method to rationally design new variants of GFP with desirable properties.…”

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 .…”