title: Functional Implications of Photosystem II Crystal Formation in Photosynthetic Membranes.
abstract: The structural organization of proteins in biological membranes can affect their function. Photosynthetic thylakoid membranes in chloroplasts have the remarkable ability to change their supramolecular organization between disordered and semicrystalline states. Although the change to the semicrystalline state is known to be triggered by abiotic factors, the functional significance of this protein organization has not yet been understood. Taking advantage of an Arabidopsis thaliana fatty acid desaturase mutant (fad5) that constitutively forms semicrystalline arrays, we systematically test the functional implications of protein crystals in photosynthetic membranes. Here, we show that the change into an ordered state facilitates molecular diffusion of photosynthetic components in crowded thylakoid membranes. The increased mobility of small lipophilic molecules like plastoquinone and xanthophylls has implications for diffusion-dependent electron transport and photoprotective energy-dependent quenching. The mobility of the large photosystem II supercomplexes, however, is impaired, leading to retarded repair of damaged proteins. Our results demonstrate that supramolecular changes into more ordered states have differing impacts on photosynthesis that favor either diffusion-dependent electron transport and photoprotection or protein repair processes, thus fine-tuning the photosynthetic energy conversion.
authors.affiliation: From the Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Tietz
authors.affiliation: From the Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340.
authors.forename: Sujith
authors.initials: S
authors.lastname: Puthiyaveetil
authors.affiliation: From the Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340.
authors.forename: Heather M
authors.initials: HM
authors.lastname: Enlow
authors.affiliation: From the Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340.
authors.forename: Robert
authors.initials: R
authors.lastname: Yarbrough
authors.affiliation: From the Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340.
authors.forename: Magnus
authors.initials: M
authors.lastname: Wood
authors.affiliation: the Electron Microscopy Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747AG Groningen, The Netherlands.
authors.forename: Dmitry A
authors.initials: DA
authors.lastname: Semchonok
authors.affiliation: the Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4370.
authors.forename: Troy
authors.initials: T
authors.lastname: Lowry
authors.affiliation: the Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-3102, and.
authors.forename: Zhirong
authors.initials: Z
authors.lastname: Li
authors.affiliation: the Institut für Biochemie der Pflanzen, Heinrich-Heine Universität Düsseldorf, 40225 Düsseldorf, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Jahns
authors.affiliation: the Electron Microscopy Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747AG Groningen, The Netherlands.
authors.forename: Egbert J
authors.initials: EJ
authors.lastname: Boekema
authors.affiliation: the Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4370.
authors.forename: Steven
authors.initials: S
authors.lastname: Lenhert
authors.affiliation: the Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-3102, and.
authors.forename: Krishna K
authors.initials: KK
authors.lastname: Niyogi
authors.affiliation: From the Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340, kirchhh@wsu.edu.
authors.forename: Helmut
authors.initials: H
authors.lastname: Kirchhoff
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D003460:Crystallization; D004579:Electron Transport; D004583:Electrons; D036681:Fluorescence Recovery After Photobleaching; D008854:Microscopy, Electron; D009154:Mutation; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D020524:Thylakoids / Q000378:metabolism*
chemical_list: D045332:Photosystem II Protein Complex; D010100:Oxygen
keywords: macromolecular crowding; membrane structure; nonphotochemical quenching; photosynthesis; photosystem II; protein crystallization; semicrystalline arrays; thylakoid membrane