Subunit Interactions in the Chloroplast ATP Synthase

9723945 McCarty在光合作用中，光能转化为化学能，其中大部分可以作为食物使用。 由腺苷二磷酸和无机磷酸合成腺苷三磷酸是光合作用中的一个重要反应。 这种需要能量的反应是由一种著名的酶催化的，这种酶被称为ATP合酶。 这种酶是9种不同蛋白质和总共约20条多肽链的聚集体。 利用生物化学和生物物理方法以及定点突变，叶绿体ATP合酶中的蛋白质的功能将被探测。 例如，将进一步确定特定蛋白质参与催化和调节活性。 还将获得对ATP合酶结构的深入了解。 ATP合成酶是非常稳定的，尽管它的复杂性。 非共价蛋白质-蛋白质相互作用是这种稳定性的原因。 蛋白质之间的相互作用对酶的稳定性贡献最大，将被研究。 所提出的工作的意义超出了对光合作用的进一步理解。 一些细菌的线粒体和质膜含有类似于叶绿体酶的ATP合酶。 因此，对叶绿体ATP合酶的研究与氧化磷酸化直接相关。 叶绿体ATP合酶的稳定性研究也具有重要意义，因为它是研究蛋白质-蛋白质相互作用的极好模型系统。 蛋白质-蛋白质相互作用是所有生命过程的基础。

9723945 McCarty In photosynthesis light energy is converted to chemical energy, much of it in the form that can be used as food. The synthesis of adenosine 5ı-triphosphate from adenosine 5ı-diphosphate and inorganic phosphate is an essential reaction in photosynthesis. This energy requiring reaction is catalyzed by a remarkable enzymatic machine, known as the ATP synthase. This enzyme is an aggregate of nine different proteins and a total of about 20 polypeptide chains. Using biochemical and biophysical approaches as well as site-directed mutagenesis, the functions of the proteins in the chloroplast ATP synthase will be probed. For example, the involvement of specific proteins in catalysis and in regulation of activity will be further defined. Insights into the structure of the ATP synthase will also be obtained. The ATP synthase is very stable, despite its complexity. Noncovalent protein-protein interactions are responsible for this stability. Which interactions among the proteins contribute most to the stabilization of the enzyme will be studied. The proposed work has significance beyond reaching a further understanding of photosynthesis. Mitochondria and the plasma membrane of some bacteria contain an ATP synthase that is similar to the chloroplast enzyme. Thus, studies on the chloroplast ATP synthase are directly relevant to those on oxidative phosphorylation. The investigation of the stability of the chloroplast ATP synthase also assumes importance in that it is an excellent model system for the study of protein-protein interactions. Protein-protein interactions are fundamental to all of lifeıs processes.