Bassi R, Dainese P
Dipartimento di Biologia, Università di Padova, Italy.
Eur J Biochem. 1992 Feb 15;204(1):317-26. doi: 10.1111/j.1432-1033.1992.tb16640.x.
In this study, we report on the composition of a photosystem-II antenna preparation which contains three chlorophyll-a/b proteins (CP), CP29, CP24 and light-harvesting complex (LHC) II obtained from Zea mays grana membranes as previously described [Dainese, P. & Bassi, R. (1991) J. Biol. Chem. 266, 8136-8142]. We demonstrate that the three chlorophyll proteins are present in the preparation with a 3:3:9 molar ratio and that they form a supramolecular antenna complex which represents one third of the photosystem-II antenna system. Phosphorylation experiments show that this complex is involved in the mechanism of regulation of excitation-energy distribution between photosystems: phosphorylation of the membranes induces dissociation of the LHCII moiety from the CP29-CP24 moiety and changes in the aggregation state of LHCII components of the CP29-CP24-LHCII complex. The LHCII subpopulations of the complex are shown to be distinct from the total LHCII population by isoelectrofocusing analysis. On the basis of these data and in the light of the stoichiometry of photosystem-II chlorophyll-binding proteins, we propose a model for the organization of photosystem-II antenna system.
在本研究中，我们报告了一种光系统II天线制剂的组成，该制剂包含三种叶绿素a/b蛋白（CP）、CP29、CP24以及如前所述从玉米基粒膜中获得的捕光复合体（LHC）II [达内塞，P. & 巴西，R.（1991年）《生物化学杂志》266卷，8136 - 8142页]。我们证明这三种叶绿素蛋白以3:3:9的摩尔比存在于该制剂中，并且它们形成了一个超分子天线复合体，该复合体占光系统II天线系统的三分之一。磷酸化实验表明，该复合体参与了光系统之间激发能分配的调节机制：膜的磷酸化诱导LHCII部分从CP29 - CP24部分解离，并改变CP29 - CP24 - LHCII复合体中LHCII组分的聚集状态。通过等电聚焦分析表明，该复合体中的LHCII亚群与总的LHCII群体不同。基于这些数据并根据光系统II叶绿素结合蛋白的化学计量关系，我们提出了一个光系统II天线系统的组织模型。
