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Title: Molecular Mechanism of Photoactivation and Structural Location of the Cyanobacterial Orange Carotenoid Protein

Abstract

The orange carotenoid protein (OCP) plays a photoprotective role in cyanobacterial photosynthesis similar to that of nonphotochemical quenching in higher plants. Under high-light conditions, the OCP binds to the phycobilisome (PBS) and reduces the extent of transfer of energy to the photosystems. The protective cycle starts from a light-induced activation of the OCP. Detailed information about the molecular mechanism of this process as well as the subsequent recruitment of the active OCP to the phycobilisome are not known. We report here our investigation on the OCP photoactivation from the cyanobacterium Synechocystis sp. PCC 6803 by using a combination of native electrospray mass spectrometry (MS) and protein cross-linking. We demonstrate that native MS can capture the OCP with its intact pigment and further reveal that the OCP undergoes a dimer-to-monomer transition upon light illumination. The reversion of the activated form of the OCP to the inactive, dark form was also observed by using native MS. Furthermore, in vitro reconstitution of the OCP and PBS allowed us to perform protein chemical cross-linking experiments. Liquid chromatography–MS/MS analysis identified cross-linking species between the OCP and the PBS core components. Our result indicates that the N-terminal domain of the OCP is closely involved in themore » association with a site formed by two allophycocyanin trimers in the basal cylinders of the phycobilisome core. This report improves our understanding of the activation mechanism of the OCP and the structural binding site of the OCP during the cyanobacterial nonphotochemical quenching process.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1]
  1. Department of Chemistry, ‡Photosynthetic Antenna Research Center (PARC), §Department of Biology, and ∥Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130, United States
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Photosynthetic Antenna Research Center (PARC)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1384876
DOE Contract Number:  
SC0001035
Resource Type:
Journal Article
Journal Name:
Biochemistry
Additional Journal Information:
Journal Volume: 53; Journal Issue: 1; Related Information: PARC partners with Washington University in St. Louis (lead); University of California, Riverside; University of Glasgow, UK; Los Alamos National Laboratory; University of New Mexico; New Mexico Corsortium; North Carolina State University; Northwestern University; Oak Ridge National Laboratory; University of Pennsylvania; Sandia National Laboratories; University of Sheffield, UK; Journal ID: ISSN 0006-2960
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; solar (fuels), photosynthesis (natural and artificial), biofuels (including algae and biomass), bio-inspired, charge transport, membrane, synthesis (novel materials), synthesis (self-assembly)

Citation Formats

Zhang, Hao, Liu, Haijun, Niedzwiedzki, Dariusz M., Prado, Mindy, Jiang, Jing, Gross, Michael L., and Blankenship, Robert E. Molecular Mechanism of Photoactivation and Structural Location of the Cyanobacterial Orange Carotenoid Protein. United States: N. p., 2013. Web. doi:10.1021/bi401539w.
Zhang, Hao, Liu, Haijun, Niedzwiedzki, Dariusz M., Prado, Mindy, Jiang, Jing, Gross, Michael L., & Blankenship, Robert E. Molecular Mechanism of Photoactivation and Structural Location of the Cyanobacterial Orange Carotenoid Protein. United States. doi:10.1021/bi401539w.
Zhang, Hao, Liu, Haijun, Niedzwiedzki, Dariusz M., Prado, Mindy, Jiang, Jing, Gross, Michael L., and Blankenship, Robert E. Tue . "Molecular Mechanism of Photoactivation and Structural Location of the Cyanobacterial Orange Carotenoid Protein". United States. doi:10.1021/bi401539w.
@article{osti_1384876,
title = {Molecular Mechanism of Photoactivation and Structural Location of the Cyanobacterial Orange Carotenoid Protein},
author = {Zhang, Hao and Liu, Haijun and Niedzwiedzki, Dariusz M. and Prado, Mindy and Jiang, Jing and Gross, Michael L. and Blankenship, Robert E.},
abstractNote = {The orange carotenoid protein (OCP) plays a photoprotective role in cyanobacterial photosynthesis similar to that of nonphotochemical quenching in higher plants. Under high-light conditions, the OCP binds to the phycobilisome (PBS) and reduces the extent of transfer of energy to the photosystems. The protective cycle starts from a light-induced activation of the OCP. Detailed information about the molecular mechanism of this process as well as the subsequent recruitment of the active OCP to the phycobilisome are not known. We report here our investigation on the OCP photoactivation from the cyanobacterium Synechocystis sp. PCC 6803 by using a combination of native electrospray mass spectrometry (MS) and protein cross-linking. We demonstrate that native MS can capture the OCP with its intact pigment and further reveal that the OCP undergoes a dimer-to-monomer transition upon light illumination. The reversion of the activated form of the OCP to the inactive, dark form was also observed by using native MS. Furthermore, in vitro reconstitution of the OCP and PBS allowed us to perform protein chemical cross-linking experiments. Liquid chromatography–MS/MS analysis identified cross-linking species between the OCP and the PBS core components. Our result indicates that the N-terminal domain of the OCP is closely involved in the association with a site formed by two allophycocyanin trimers in the basal cylinders of the phycobilisome core. This report improves our understanding of the activation mechanism of the OCP and the structural binding site of the OCP during the cyanobacterial nonphotochemical quenching process.},
doi = {10.1021/bi401539w},
journal = {Biochemistry},
issn = {0006-2960},
number = 1,
volume = 53,
place = {United States},
year = {2013},
month = {12}
}