Bourne-Worster, Susannah;
Worth, Graham A;
(2024)
Quantum dynamics of excited state proton transfer in green fluorescent protein.
The Journal of Chemical Physics
, 160
(6)
, Article 065102. 10.1063/5.0188834.
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Abstract
Photoexcitation of green fluorescent protein (GFP) triggers long-range proton transfer along a “wire” of neighboring protein residues, which, in turn, activates its characteristic green fluorescence. The GFP proton wire is one of the simplest, most well-characterized models of biological proton transfer but remains challenging to simulate due to the sensitivity of its energetics to the surrounding protein conformation and the possibility of non-classical behavior associated with the movement of lightweight protons. Using a direct dynamics variational multiconfigurational Gaussian wavepacket method to provide a fully quantum description of both electrons and nuclei, we explore the mechanism of excited state proton transfer in a high-dimensional model of the GFP chromophore cluster over the first two picoseconds following excitation. During our simulation, we observe the sequential starts of two of the three proton transfers along the wire, confirming the predictions of previous studies that the overall process starts from the end of the wire furthest from the fluorescent chromophore and proceeds in a concerted but asynchronous manner. Furthermore, by comparing the full quantum dynamics to a set of classical trajectories, we provide unambiguous evidence that tunneling plays a critical role in facilitating the leading proton transfer.
| Type: | Article |
|---|---|
| Title: | Quantum dynamics of excited state proton transfer in green fluorescent protein |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1063/5.0188834 |
| Publisher version: | http://dx.doi.org/10.1063/5.0188834 |
| Language: | English |
| Additional information: | © 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
| Keywords: | Excited states, Potential energy surfaces, Quantum mechanical/molecular mechanical calculations, Computational methods, Kinetic isotope effects, Photoexcitations, Excited state reaction dynamics, Quantum tunneling, Biophysical chemistry, Proteins |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10187458 |
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