Lipid-induced conformational changes within the cytochrome b6f complex of oxygenic photosynthesis.

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TitleLipid-induced conformational changes within the cytochrome b6f complex of oxygenic photosynthesis.
Publication TypeJournal Article
Year of Publication2013
AuthorsS Hasan, S, Stofleth, JT, Yamashita, E, Cramer, WA
JournalBiochemistry
Volume52
Issue15
Pagination2649-54
Date Published2013 Apr 16
ISSN1520-4995
KeywordsCrystallography, X-Ray, Cyanobacteria, Cytochrome b6f Complex, Iron-Sulfur Proteins, Lipids, Models, Molecular, Phosphatidylglycerols, Photosynthesis, Protein Conformation, Protein Structure, Tertiary
Abstract

Cytochrome b6f catalyzes quinone redox reactions within photosynthetic membranes to generate a transmembrane proton electrochemical gradient for ATP synthesis. A key step involves the transfer of an electron from the [2Fe-2S] cluster of the iron-sulfur protein (ISP) extrinsic domain to the cytochrome f heme across a distance of 26 Å, which is too large for competent electron transfer but could be bridged by translation-rotation of the ISP. Here we report the first crystallographic evidence of significant motion of the ISP extrinsic domain. It is inferred that extensive crystallographic disorder of the ISP extrinsic domain indicates conformational flexibility. The ISP disorder observed in this structure, in contrast to the largely ordered ISP structure observed in the b6f complex supplemented with neutral lipids, is attributed to electrostatic interactions arising from anionic lipids.

DOI10.1021/bi301638h
Alternate JournalBiochemistry
PubMed ID23514009
PubMed Central IDPMC4034689
Grant ListR01 GM038323 / GM / NIGMS NIH HHS / United States
R56 GM038323 / GM / NIGMS NIH HHS / United States
GM-038323 / GM / NIGMS NIH HHS / United States