Delayed vibrational modulation of the solvated GFP chromophore into a conical intersection
Miles A Taylor1, Liangdong Zhu, Nikita D Rozanov
1Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA. Chong.Fang@oregonstate.edu.
Physical Chemistry Chemical Physics : PCCP
|April 30, 2019
Summary
Researchers mapped the energy dissipation pathways of the green fluorescent protein (GFP) chromophore model, HBDI, using femtosecond stimulated Raman spectroscopy (FSRS). This study reveals crucial vibrational couplings and intermediate states during the isomerization reaction, aiding in designing new fluorescent probes.
Area of Science:
- Photochemistry
- Spectroscopy
- Biophysics
Background:
- Green fluorescent protein (GFP) is vital in bioimaging, but its isolated chromophore lacks fluorescence.
- Understanding chromophore excited-state dynamics is key to developing new fluorescent probes and molecular machines.
Purpose of the Study:
- To elucidate the energy dissipation pathways and excited-state dynamics of the GFP model chromophore (HBDI) in solution.
- To investigate the role of vibrational couplings and intermediate states in the HBDI isomerization reaction.
Main Methods:
- Utilized tunable femtosecond stimulated Raman spectroscopy (FSRS) and transient absorption (TA).
- Employed a 550 nm Raman pump to enhance excited-state vibrational motions.
- Analyzed vibrational couplings and reaction dynamics using wavelet transform and solvent mixture studies.
Main Results:
- Identified prominent anharmonic couplings between vibrational modes (∼227, 866, and 1572 cm-1) during HBDI isomerization.
- Revealed a delayed onset of coupling peaks correlated with an intermediate charge-separated state formation.
- Observed altered dynamics and coupling in a water-glycerol mixture, supporting the proposed mechanism.
Conclusions:
- Provided a real-time molecular movie of the HBDI isomerization reaction, detailing its passage through a conical intersection to the twisted intramolecular charge transfer (TICT) state.
- Established a foundation for the rational design of efficient molecular rotors and fluorescent probes based on GFP chromophore dynamics.
More Related Videos
Related Concept Videos
02:05Entropy and Solvation
8.3K
The process of surrounding a solute with solvent is called solvation. It involves evenly distributing the solute within the solvent. The rule of thumb for determining a solvent for a given compound is that like dissolves like. A good solvent has molecular characteristics similar to those of the compound to be dissolved. For example, polar solutions dissolve polar solutes, and apolar solvents dissolve apolar solutes. A polar solvent is a solvent that has a high dielectric constant (ϵ...
8.3K
02:12Solvating Effects
8.5K
An understanding of the solvating effect helps rationalize the relation between solvation and acidity of the compound. In addition, this also explains the relative stability of conjugate bases for compounds with different pKa values. This lesson details, in-depth, the principle of solvating effects. The strength of an acid and the stability of its corresponding conjugate base are determined using pKa values. This observed relationship is a consequence of solvation, which is the interaction...
8.5K
01:19Vibrating Concrete
387
Mechanical vibrators are instrumental in compacting newly poured concrete within formwork and around reinforcements. This process is essential to eliminate trapped air pockets and establish a dense concrete mass. One widely used method is vibrating by internal vibrators, often referred to as a poker vibrator or immersion vibrator. It is rapidly inserted through the full depth of the freshly laid concrete and slightly extends into the layer below it (which remains in a plastic state). Consistent...
387
01:24IR Spectroscopy: Molecular Vibration Overview
4.6K
When Infrared (IR) radiation passes through a covalently bonded molecule, the bonds transition from lower to higher vibrational levels. The fundamental vibrational motions that result in infrared absorption can be classified as stretching or bending vibrations.
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
4.6K
01:08IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
1.8K
Identical bonds within a polyatomic group can stretch symmetrically (in-phase) or asymmetrically (out-of-phase). Similar to hydrogen bonding, these vibrations also influence the shape of the IR peak. Generally, asymmetric stretching frequencies are higher than symmetric stretching frequencies. For example, primary amines exhibit two distinct IR peaks between 3300–3500 cm−1 corresponding to the symmetric and asymmetric N-H stretching, while secondary amines exhibit a single...
1.8K
01:16IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
2.8K
A covalently bonded heteronuclear diatomic molecule can be modeled as two vibrating masses connected by a spring. The vibrational frequency of the bond can be expressed using an equation derived from Hooke's law, which describes how the force applied to stretch or compress a spring is proportional to the displacement of the spring. In this case, the atoms behave like masses, and the bond acts like a spring.
According to Hooke's law, the vibrational frequency is directly proportional to...
According to Hooke's law, the vibrational frequency is directly proportional to...
2.8K