Time-resolved crystallographic studies of light-induced structural changes in the photosynthetic reaction center

Richard H.G. Baxter, Nina Ponomarenko, Vukica Šrajer, Reinhard Pahl, Keith Moffatt, James R. Norris

Research output: Contribution to journalArticlepeer-review

60 Scopus citations

Abstract

Light-induced structural changes in the bacterial reaction center were studied by a time-resolved crystallographic experiment. Crystals of protein from Blastochloris viridis (formerly Rhodopseudomonas viridis) were reconstituted with ubiquinone and analyzed by monochromatic and Laue diffraction, in the dark and 3 ms after illuminating the crystal with a pulsed laser (630 nm, 3 mJ/pulse, 7 ns duration). Refinement of monochromatic data shows that ubiquinone binds only in the "proximal" QB binding site. No significant structural difference was observed between the light and dark datasets; in particular, no quinone motion was detected. This result may be reconciled with previous studies by postulating equilibration of the "distal" and "proximal" binding sites upon extended dark adaption, and in which movement of ubiquinone is not the conformational gate for the first electron transfer between QA and QB.

Original languageEnglish
Pages (from-to)5982-5987
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume101
Issue number16
DOIs
StatePublished - Apr 20 2004

Keywords

  • Crystallography, X-Ray
  • Fourier Analysis
  • Light
  • Models, Molecular
  • Photosynthetic Reaction Center Complex Proteins/chemistry
  • Protein Conformation
  • Rhodopseudomonas/chemistry

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