Primary Citation of Related Structures: 9EYS, 9I9L
PubMed Abstract:
The discovery of chlorophyll f-containing photosystems, with their long-wavelength photochemistry, represented a distinct, low-energy paradigm for oxygenic photosynthesis. Structural studies on chlorophyll f-containing photosystem I could identify some chlorophylls f sites, but none among the photochemically active pigments and concluded that chlorophyll f plays no photochemical role. Here, we report two cryo-EM structures of far-red PSI from Chroococcidiopsis thermalis PCC 7203, allowing the assignment of eight chlorophylls f molecules, including the redox active A -1B . Simulations of absorption difference spectra induced by charge separation indicate that the experimental spectra can be reproduced only by considering the presence of a chlorophyll f at the A -1B site. The chlorophyll f locations, wavelength assignments, and conserved far-red-specific residues provide functional insights for efficient use of long wavelength photons.
Organizational Affiliation:
Department of Life Sciences, Imperial College, London, UK.
Department of Physics, Imperial College, London, UK.
Institute for Theoretical Physics, Johannes Kepler University, Linz, Austria.
Centre for Structural Biology, Imperial College, London, UK.
Sargent Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, London, UK.
CK [auth U] CP [auth g] FP [auth h] IF [auth L] JE [auth B]
CK [auth U], CP [auth g], FP [auth h], IF [auth L], JE [auth B], LE [auth B], LK [auth W], MC [auth A], OP [auth j], RJ [auth O], SH [auth N], TO [auth b], VE [auth I], YE [auth J], ZJ [auth T]
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