Local protein solvation drives direct down-conversion in phycobiliprotein PC645 via incoherent vibronic transport.

ABSTRACT: The mechanisms controlling excitation energy transport (EET) in light-harvesting complexes remain controversial. Following the observation of long-lived beats in 2D electronic spectroscopy of PC645, vibronic coherence, the delocalization of excited states between pigments supported by a resonant vibration, has been proposed to enable direct excitation transport from the highest-energy to the lowest-energy pigments, bypassing a collection of intermediate states. Here, we instead show that for phycobiliprotein PC645 an incoherent vibronic transport mechanism is at play. We quantify the solvation dynamics of individual pigments using ab initio quantum mechanics/molecular mechanics (QM/MM) nuclear dynamics. Our atomistic spectral densities reproduce experimental observations ranging from absor

SUBMITTER: Blau SM 

PROVIDER: S-EPMC5899487 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature