title: Dynamic control of protein diffusion within the granal thylakoid lumen.
abstract: The machinery that conducts the light-driven reactions of oxygenic photosynthesis is hosted within specialized paired membranes called thylakoids. In higher plants, the thylakoids are segregated into two morphological and functional domains called grana and stroma lamellae. A large fraction of the luminal volume of the granal thylakoids is occupied by the oxygen-evolving complex of photosystem II. Electron microscopy data we obtained on dark- and light-adapted Arabidopsis thylakoids indicate that the granal thylakoid lumen significantly expands in the light. Models generated for the organization of the oxygen-evolving complex within the granal lumen predict that the light-induced expansion greatly alleviates restrictions imposed on protein diffusion in this compartment in the dark. Experiments monitoring the redox kinetics of the luminal electron carrier plastocyanin support this prediction. The impact of the increase in protein mobility within the granal luminal compartment in the light on photosynthetic electron transport rates and processes associated with the repair of photodamaged photosystem II complexes is discussed.
authors: Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA. kirchhh@wsu.edu
authors: Helmut
authors: H
authors: Kirchhoff
authors: Chris
authors: C
authors: Hall
authors: Magnus
authors: M
authors: Wood
authors: Miroslava
authors: M
authors: Herbstová
authors: Onie
authors: O
authors: Tsabari
authors: Reinat
authors: R
authors: Nevo
authors: Dana
authors: D
authors: Charuvi
authors: Eyal
authors: E
authors: Shimoni
authors: Ziv
authors: Z
authors: Reich
mesh_terms: D017360:Arabidopsis / Q000378:metabolism* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000378:metabolism*; D060365:Chloroplast Proteins / Q000378:metabolism*; D045348:Cytochromes f / Q000378:metabolism; D003624:Darkness; D004058:Diffusion; D007700:Kinetics; D008954:Models, Biological; D010084:Oxidation-Reduction; D020524:Thylakoids / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D029681:Arabidopsis Proteins; D060365:Chloroplast Proteins; D045348:Cytochromes f