Mechanism and Inhibition of Pyruvate Phosphate Dikinase

描述(由申请人提供)：本修订申请申请拨款至 丙酮酸磷酸酶对分离位点催化作用的继续研究 二激酶(PPDK)。PPDK催化ATP、PI和丙酮酸的相互转化 AMP、PPI和PEP通过使用由运营商链接的两个单独的活动站点 组氨酸残留物。拟议研究的总体目标是确定 载体组氨酸在活性部位之间转移的机制 通过精确定向和定时的域域对接步骤。这些研究 将提供对控制瞬变力的更深层次的理解 信号转导途径和模板中蛋白质-蛋白质复合体的形成 定向的生物合成途径。列出了五个具体目标。这些是(1) 确定了PPDK构象2的X射线晶体结构，(2)确定了 域链接器在促进域-域成功对接中的作用，(3) 确定结构域-结构域界面残基之间的相互作用在 促进正确的对接方向和优化停留时间，(4) 区分穿透溶剂区扩散模型和 滑动结构域模型和(5)确定PPDK同源物在 结核分枝杆菌。这最后一个目标将实现的目的是 发现一种新的代谢途径在这种病原体中起作用，因为 也是药物设计的新靶点。

DESCRIPTION (provided by applicant): This revised application requests funds to continue studies of separate site catalysis by the enzyme pyruvate phosphate dikinase (PPDK). PPDK catalyzes the interconversion of ATP, Pi, and pyruvate with AMP, PPi and PEP by using two separate active sites linked by a carrier histidine residue. The overall goal of the proposed studies is to determine the mechanism by which the carrier histidine is transferred between active sites through precisely oriented and timed domain-domain docking steps. These studies will provide a deeper understanding of the forces controlling transient protein-protein complex formation in signal transduction pathways and template directed biosynthetic pathways. Five specific aims are listed. These are (1) determine the X-ray crystal structure of PPDK conformer 2, (2) determine the role of domain linkers in facilitating successful domain-domain docking, (3) determine the role of interactions between domain-domain interface residues in facilitating correct docking orientation and in optimizing residence time, (4) distinguish between a through-solvent-domain-diffusion model and a sliding-domain model and (5) identify the role of the PPDK homologue in Mycobacterium tuberculosis. This last aim will be carried out for the purpose of discovering a novel metabolic pathway operating with in this pathogen, as well as a novel target for drug design.