Two-Dimensional Electronic Spectroscopy Reveals Ultrafast Downhill Energy Transfer in Photosystem I Trimers of the Cyanobacterium Thermosynechococcus elongatus

Jessica M Anna; Evgeny E Ostroumov; Karim Maghlaoui; James Barber; Gregory D Scholes

doi:10.1021/jz3018013

Two-Dimensional Electronic Spectroscopy Reveals Ultrafast Downhill Energy Transfer in Photosystem I Trimers of the Cyanobacterium Thermosynechococcus elongatus

J Phys Chem Lett. 2012 Dec 20;3(24):3677-84. doi: 10.1021/jz3018013. Epub 2012 Nov 30.

Authors

Jessica M Anna¹, Evgeny E Ostroumov¹, Karim Maghlaoui², James Barber², Gregory D Scholes¹

Affiliations

¹ †Department of Chemistry, Institute for Optical Sciences and Centre for Quantum Information and Quantum Control, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
² ‡Division of Molecular Bioscience, Department of Life Sciences, Imperial College London, Sir Ernst Chain Building - Wolfson Laboratories, South Kensington Campus, London, SW7 2AZ, United Kingdom.

PMID: 26291095
DOI: 10.1021/jz3018013

Abstract

Two-dimensional electronic spectroscopy (2DES) was used to investigate the ultrafast energy-transfer dynamics of trimeric photosystem I of the cyanobacterium Thermosynechococcus elongatus. We demonstrate the ability of 2DES to resolve dynamics in a large pigment-protein complex containing ∼300 chromophores with both high frequency and time resolution. Monitoring the waiting-time-dependent changes of the line shape of the inhomogeneously broadened Qy(0-0) transition, we directly observe downhill energy equilibration on the 50 fs time scale.

Keywords: energy transfer; light harvesting; phasing; photosynthesis; ultrafast spectroscopy.