Functions of the Subunits of the Chloroplast ATP Synthase

叶绿体、线粒体和细菌膜ATP合成酶的结构、机制和调控是生物化学中的主要问题。本研究涉及活性形式的叶绿体ATP合成酶的整体膜部分CFo亚基的纯化，以及质子易位的重组和合成酶的外部催化部分cf1的结合。荧光共振能量转移将用于将CF1的广泛结构图扩展到CFo。核苷酸与CF1的结合与初始催化速率的关系将被检查。量热分析可以提供有关atp诱导的CF1构象变化的信息，以及核苷酸结合在稳定酶中的作用。将进行第四个核苷酸结合位点的结构作图。我们将研究CF1的epsilon亚基的作用。将通过荧光和等温滴定量热法研究epsilon与该亚基CF1缺陷的结合。

The structure, mechanism and regulation of the ATP synthases of chloroplast, mitochondrial, and bacterial membranes are major problems in biochemistry. This proposal deals with chloroplast purification of the subunits of CFo, the integral membrane portion of the chloroplast ATP synthase, in active form, and the reconstituted of proton translocation and the binding of CF 1, the extrinsic, catalytic part of the synthase. Fluorescence resonance energy transfer will be used to extend the extensive structural map obtained for CF1 to CFo. The binding of nucleotides to CF1 in relation to initial rates of catalysis will be examined. Calorimetric analyses are proposed that should give information about ATP-induced conformational changes in CF1 as well as about the role of nucleotide binding in stabilizing the enzyme. Structural mapping of a fourth nucleotide binding site will be carried out. The role of the epsilon subunit of CF1 will be examined. The binding of epsilon to CF1 deficient in this subunit will be studied by fluorescence and by isothermal titration calorimetry.