The Fenna–Matthews–Olson Protein Revisited: A Fully Polarizable (TD)DFT/MM Description

Title	The Fenna–Matthews–Olson Protein Revisited: A Fully Polarizable (TD)DFT/MM Description
Publication Type	Journal Article
Year of Publication	2014
Authors	Jurinovich, S, Curutchet C, Mennucci B
Journal	ChemPhysChem
Volume	15
Pagination	3194–3204
ISSN	1439-7641
Keywords	density functional calculations, energy transfer, molecular electronics, molecular modeling, protein models
Abstract	We report a combined molecular dynamics and quantum mechanics (QM)/molecular mechanics (MM) analysis of the excitonic properties of the Fenna–Matthews–Olson (FMO) protein by using a polarizable MM model combined with a time-dependent density functional theory description. Overall, our results indicate that structural fluctuations, electrostatic interactions, and short-range quantum effects can significantly modulate the model Hamiltonian parameters (site energies and couplings). We find that the specific interactions with the axial ligand and the hydrogen-bonded residues are responsible for the energy ladder, with their effects being mainly due to electrostatic interactions, but with short-range quantum contributions that are not negligible. In addition, a striking modulation of the screening effects experienced by the BChl pairs, due to the heterogeneous polarizability of the FMO and solvent environment, is observed. Finally, we find that the exciton model gives a reliable description of the delocalized excited states in the complex.
URL	http://dx.doi.org/10.1002/cphc.201402244
DOI	10.1002/cphc.201402244

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