Origin of the two bands in the B800 ring and their involvement in the energy transfer network of Allochromatium vinosum

Schröter, M., Alcocer, M. J.P., Cogdell, R. J. , Kühn, O. and Zigmantas, D. (2018) Origin of the two bands in the B800 ring and their involvement in the energy transfer network of Allochromatium vinosum. Journal of Physical Chemistry Letters, 9(6), pp. 1340-1345. (doi: 10.1021/acs.jpclett.8b00438) (PMID:29488385)

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Abstract

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 Allochromatium vinosum is particularly distinct, featuring a double peak structure in its B800 absorption band. Two hypotheses-not necessarily mutually exclusive-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.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Cogdell, Professor Richard
Authors: Schröter, M., Alcocer, M. J.P., Cogdell, R. J., Kühn, O., and Zigmantas, D.
College/School:College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
Journal Name:Journal of Physical Chemistry Letters
Publisher:American Chemical Society
ISSN:1948-7185
ISSN (Online):1948-7185
Published Online:28 February 2018

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