Abstract
Photosynthetic reaction centres harvest the energy content of sunlight by transporting electrons across an energy-transducing biological membrane. Here we use time-resolved serial femtosecond crystallography1 using an X-ray free-electron laser2 to observe light-induced structural changes in the photosynthetic reaction centre of Blastochloris viridis on a timescale of picoseconds. Structural perturbations first occur at the special pair of chlorophyll molecules of the photosynthetic reaction centre that are photo-oxidized by light. Electron transfer to the menaquinone acceptor on the opposite side of the membrane induces a movement of this cofactor together with lower amplitude protein rearrangements. These observations reveal how proteins use conformational dynamics to stabilize the charge-separation steps of electron-transfer reactions.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Bacteriochlorophylls / metabolism
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Binding Sites / drug effects
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Chlorophyll / metabolism
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Chlorophyll / radiation effects
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Crystallography
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Cytoplasm / metabolism
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Electron Transport / drug effects
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Electrons
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Hyphomicrobiaceae / enzymology
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Hyphomicrobiaceae / metabolism
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Lasers
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Models, Molecular
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Oxidation-Reduction / radiation effects
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Pheophytins / metabolism
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Photosynthetic Reaction Center Complex Proteins / chemistry*
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Photosynthetic Reaction Center Complex Proteins / metabolism*
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Photosynthetic Reaction Center Complex Proteins / radiation effects
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Protons
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Ubiquinone / analogs & derivatives
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Ubiquinone / metabolism
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Vitamin K 2 / metabolism
Substances
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Bacteriochlorophylls
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Pheophytins
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Photosynthetic Reaction Center Complex Proteins
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Protons
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Vitamin K 2
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Ubiquinone
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Chlorophyll
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bacteriopheophytin
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ubiquinol