1 research outputs found
Origin of the Two Bands in the B800 Ring and Their Involvement in the Energy Transfer Network of <i>Allochromatium vinosum</i>
Bacterial
photosynthesis features robust and adaptable energy-harvesting
processes in which light-harvesting proteins play a crucial role.
The peripheral light-harvesting complex of the purple bacterium <i>Allochromatium vinosum</i> is particularly distinct, featuring
a double peak structure in its B800 absorption band. Two hypothesesî—¸not
necessarily mutually exclusiveî—¸concerning the origin of this
splitting have been proposed; either two distinct B800 bacteriochlorophyll
site energies are involved, or an excitonic dimerization of bacteriochlorophylls
within the B800 ring takes place. Through the use of two-dimensional
electronic spectroscopy, we present unambiguous evidence that excitonic
interaction shapes the split band. We further identify and characterize
all of the energy transfer pathways within this complex by using a
global kinetic fitting procedure. Our approach demonstrates how the
combination of two-dimensional spectral resolution and self-consistent
fitting allows for extraction of information on light-harvesting processes,
which would otherwise be inaccessible due to signal congestion