Title

Structure of a monomeric photosystem II core complex from a cyanobacterium acclimated to far-red light reveals the functions of chlorophylls d and f

Authors

Christopher J. Gisriel, Department of Chemistry, Yale University, New Haven, Connecticut, USA.
Gaozhong Shen, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA.
Ming-Yang Ho, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Intercollege Graduate Program in Plant Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Life Science, National Taiwan University, Taipei, Taiwan.
Vasily Kurashov, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA.
David A. Flesher, Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA.
Jimin Wang, Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA.
William H. Armstrong, Department of Chemistry, Boston College, Chestnut Hill, Massachusetts, USA.
John H. Golbeck, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, USA.
Marilyn R. Gunner, Department of Physics, City College of New York, New York, New York, USA.
David J. Vinyard, Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA.
Richard J. Debus, Department of Biochemistry, University of California, Riverside, California, USA.
Gary W. Brudvig, Department of Chemistry, Yale University, New Haven, Connecticut, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA. Electronic address: gary.brudvig@yale.edu.
Donald A. Bryant, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Intercollege Graduate Program in Plant Biology, The Pennsylvania State University, University Park, Pennsylvania, USA. Electronic address: dab14@psu.edu.

Document Type

Article

Publication Date

1-1-2022

Abstract

Far-red light (FRL) photoacclimation in cyanobacteria provides a selective growth advantage for some terrestrial cyanobacteria by expanding the range of photosynthetically active radiation to include far-red/near-infrared light (700-800 nm). During this photoacclimation process, photosystem II (PSII), the water:plastoquinone photooxidoreductase involved in oxygenic photosynthesis, is modified. The resulting FRL-PSII is comprised of FRL-specific core subunits and binds chlorophyll (Chl) d and Chl f molecules in place of several of the Chl a molecules found when cells are grown in visible light. These new Chls effectively lower the energy canonically thought to define the "red limit" for light required to drive photochemical catalysis of water oxidation. Changes to the architecture of FRL-PSII were previously unknown, and the positions of Chl d and Chl f molecules had only been proposed from indirect evidence. Here, we describe the 2.25 Å resolution cryo-EM structure of a monomeric FRL-PSII core complex from Synechococcus sp. PCC 7335 cells that were acclimated to FRL. We identify one Chl d molecule in the Chl position of the electron transfer chain and four Chl f molecules in the core antenna. We also make observations that enhance our understanding of PSII biogenesis, especially on the acceptor side of the complex where a bicarbonate molecule is replaced by a glutamate side chain in the absence of the assembly factor Psb28. In conclusion, these results provide a structural basis for the lower energy limit required to drive water oxidation, which is the gateway for most solar energy utilization on earth.

Publication Source (Journal or Book title)

The Journal of biological chemistry

First Page

101424

This document is currently not available here.

COinS