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Title: | Theoretical characterization of the spectral density of the water-soluble chlorophyll-binding protein from combined quantum mechanics/molecular mechanics molecular dynamics simulations |
Author: | Rosnik, Andreana M. R Curutchet Barat, Carles E. |
Keywords: | Llum Fotosíntesi Química quàntica Química física Light Photosynthesis Quantum chemistry Physical and theoretical chemistry |
Issue Date: | 8-Dec-2015 |
Publisher: | American Chemical Society |
Abstract: | Over the past decade, both experimentalists and theorists have worked to develop methods to describe pigment-protein coupling in photosynthetic light-harvesting complexes in order to understand the molecular basis of quantum coherence effects observed in photosynthesis. Here we present an improved strategy based on the combination of quantum mechanics/molecular mechanics (QM/MM) molecular dynamics (MD) simulations and excited-state calculations to predict the spectral density of electronic-vibrational coupling. We study the water-soluble chlorophyll-binding protein (WSCP) reconstituted with Chl a or Chl b pigments as the system of interest and compare our work with data obtained by Pieper and co-workers from differential fluorescence line-narrowing spectra (Pieper et al. J. Phys. Chem. B 2011, 115 (14), 4042−4052). Our results demonstrate that the use of QM/MM MD simulations where the nuclear positions are still propagated at the classical level leads to a striking improvement of the predicted spectral densities in the middle- and high-frequency regions, where they nearly reach quantitative accuracy. This demonstrates that the so-called 'geometry mismatch' problem related to the use of low-quality structures in QM calculations, not the quantum features of pigments high-frequency motions, causes the failure of previous studies relying on similar protocols. Thus, this work paves the way toward quantitative predictions of pigment-protein coupling and the comprehension of quantum coherence effects in photosynthesis. |
Note: | Versió postprint del document publicat a: https://doi.org/10.1021/acs.jctc.5b00891 |
It is part of: | Journal of Chemical Theory and Computation, 2015, vol. 11, num. 12, p. 5826-5837 |
URI: | http://hdl.handle.net/2445/175614 |
Related resource: | https://doi.org/10.1021/acs.jctc.5b00891 |
ISSN: | 1549-9618 |
Appears in Collections: | Articles publicats en revistes (Farmàcia, Tecnologia Farmacèutica i Fisicoquímica) |
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