analysis of the chloroplast protein kinase stt7 during state transitions分析叶绿体蛋白激酶stt7在状态转换.pdfVIP

PLoS BIOLOGY Analysis of the Chloroplast Protein Kinase Stt7 during State Transitions 1,2 1,2 ` 1,2¤ 1,2 3 Sylvain Lemeille , Adrian Willig , Nathalie Depege-Fargeix , Christian Delessert , Roberto Bassi , Jean-David Rochaix1,2* 1 Department of Molecular Biology University of Geneva, Geneva, Switzerland, 2 Department of Plant Biology, University of Geneva, Geneva, Switzerland, 3 University of Verona, Faculty of Sciences, Verona, Italy State transitions allow for the balancing of the light excitation energy between photosystem I and photosystem II and for optimal photosynthetic activity when photosynthetic organisms are subjected to changing light conditions. This process is regulated by the redox state of the plastoquinone pool through the Stt7/STN7 protein kinase required for phosphorylation of the light-harvesting complex LHCII and for the reversible displacement of the mobile LHCII between the photosystems. We show that Stt7 is associated with photosynthetic complexes including LHCII, photosystem I, and the cytochrome b6f complex. Our data reveal that Stt7 acts in catalytic amounts. We also provide evidence that Stt7 contains a transmembrane region that separates its catalytic kinase domain on the stromal side from its N-terminal end in the thylakoid lumen with two conserved Cys that are critical for its activity and state transitions. On the basis of these data, we propose that the activity of Stt7 is regulated through its transmembrane domain and that a disulfide bond between the two lumen Cys is essential for its activity. The