Origin of the Two Bands in the B800 Ring and Their Involvement in the Energy Transfer Network of Allochromatium vinosum

Summary, in English

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.

• Author: Marco Schröter; Marcelo J.P. Alcocer; Richard J. Cogdell; Oliver Kühn; Donatas Zigmantas
• Department/s: Chemical Physics; NanoLund: Centre for Nanoscience
• Publishing year: 2018-03-15
• Language: English
• Pages: 1340-1345
• Publication/Series: Journal of Physical Chemistry Letters
• Volume: 9
• Issue: 6
• Links: http://dx.doi.org/10.1021/acs.jpclett.8b00438
• Document type: Journal article
• Publisher: The American Chemical Society (ACS)
• Topic: Physical Chemistry (including Surface- and Colloid Chemistry); Atom and Molecular Physics and Optics
• Status: Published
• ISBN/ISSN/Other: ISSN: 1948-7185