Spatial and Electronic Correlations in the PE545 Light-Harvesting Complex

TitleSpatial and Electronic Correlations in the PE545 Light-Harvesting Complex
Publication TypeJournal Article
Year of Publication2013
AuthorsViani, L, Curutchet C, Mennucci B
JournalJournal of Physical Chemistry Letters
Pagination372 - 377
Date Published2013
ISBN Number1948-7185
Keywordsenergy-transfer, molecular-dynamics, motions, phycoerythrin, Protein, quantum coherence, resolution, simulations, spectra, temperature
AbstractThe recent discovery of long-lasting quantum coherence effects in photosynthetic pigment-protein complexes has challenged our view of the role that protein motions play in light-harvesting processes. Several groups have suggested that correlated fluctuations involving the pigments site energies and couplings could be at the origin of such unexpected behavior. Here we combine molecular dynamics simulations with quantum mechanics/molecular mechanics calculations to analyze the degree of correlated fluctuations in the PE545 complex of Rhodomonas sp. strain CS24. We find that correlations between the motions of the chromophores, which are significantly assisted by the water solvent, do not translate into appreciable site energy correlations but do lead to significant cross-correlations of energies and couplings. Such behavior, not observed in a recent study on the Fenna-Mathews-Olson complex, seems to provide phycobiliproteins with an additional fundamental mechanism to control quantum coherence and light-harvesting efficiency compared with chlorophyll-containing complexes.