The 2.4 Å cryo-EM structure of a heptameric light-harvesting 2 complex reveals two carotenoid energy transfer pathways

Gardiner, A. T., Naydenova, K., Castro-Hartmann, P., Nguyen-Phan, C. T., Russo, C. J., Sader, K., Hunter, C. N., Cogdell, R. J. and Qian, P. (2021) The 2.4 Å cryo-EM structure of a heptameric light-harvesting 2 complex reveals two carotenoid energy transfer pathways. Science Advances, 7(7), eabe4650. (doi: 10.1126/sciadv.abe4650) (PMID:33579696) (PMCID:PMC7880592)

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Abstract

We report the 2.4 Ångström resolution structure of the light-harvesting 2 (LH2) complex from Marichromatium (Mch.) purpuratum determined by cryogenic electron microscopy. The structure contains a heptameric ring that is unique among all known LH2 structures, explaining the unusual spectroscopic properties of this bacterial antenna complex. We identify two sets of distinct carotenoids in the structure and describe a network of energy transfer pathways from the carotenoids to bacteriochlorophyll a molecules. The geometry imposed by the heptameric ring controls the resonant coupling of the long-wavelength energy absorption band. Together, these details reveal key aspects of the assembly and oligomeric form of purple bacterial LH2 complexes that were previously inaccessible by any technique.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Cogdell, Professor Richard and Nguyen Phan, Cam Tu and Gardiner, Dr Alastair
Authors: Gardiner, A. T., Naydenova, K., Castro-Hartmann, P., Nguyen-Phan, C. T., Russo, C. J., Sader, K., Hunter, C. N., Cogdell, R. J., and Qian, P.
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Science Advances
Publisher:American Association for the Advancement of Science
ISSN:2375-2548
ISSN (Online):2375-2548
Copyright Holders:Copyright © 2021 The Authors
First Published:First published in Science Advances 7(7):eabe4650
Publisher Policy:Reproduced under a Creative Commons licence

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