Mechanism and Inhibition of Pyruvate Phosphate Dikinase

描述（由申请人提供）：此修订后的申请要求资金， 继续研究丙酮酸磷酸酶的分离位点催化作用 二激酶（PPDK）。PPDK催化ATP、Pi和丙酮酸的相互转化 通过使用由载体连接的两个单独的活性位点与AMP、PPi和PEP 组氨酸残基。拟议研究的总体目标是确定 载体组氨酸在活性位点之间转移的机制 通过精确定向和定时的域-域对接步骤。这些研究 将提供对控制瞬态的力的更深入的理解 信号转导途径中蛋白质-蛋白质复合物的形成和模板 定向生物合成途径。列出了五个具体目标。这些是（1） 确定PPDK构象异构体2的X射线晶体结构，（2）确定PPDK构象异构体2的X射线晶体结构。 结构域接头在促进成功的结构域-结构域对接中的作用，（3） 确定结构域-结构域界面残基之间的相互作用在 有利于正确的对接方向和优化停留时间，（4） 区分通过溶剂域扩散模型和 滑动结构域模型和（5）确定PPDK同源物的作用， 结核分枝杆菌。这最后一个目标将被执行的目的， 发现了一种新的代谢途径， 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.