Oxime-Assisted Catalysis of Organophosphates and Reactivation of AChE

描述（由申请人提供）：我们提出的项目旨在通过设计突变的人乙酰胆碱酯酶（AChE）、新型肟和相关的再活化亲核试剂来改善有机磷神经毒剂有机磷暴露的预防和治疗。这种“肟辅助催化”的策略改变了乙酰胆碱酯酶，使得当置于循环中时，肟和乙酰胆碱酯酶成为有机磷酸酯的催化剂，而不是化学计量的清除剂。已经建立了一系列有机磷酸酯水解的原理证明，我们将改进AChE突变和肟结构，以提高水解和保留在等离子体空间中的催化速率。由于肟治疗，2-PAM和HI-6，也重新激活抑制乙酰胆碱酯酶在目标网站和长期肟治疗的治疗效益已成为最近得到充分赞赏，我们建议设计新的再激活剂的基础上当代知识的乙酰胆碱酯酶结构，我们和其他团体在过去的二十年中作出了贡献。该方法将活性中心峡谷的冲击和肟的进入角度视为设计策略中的限制约束。此外，UCSD和TSRI集团已经应用了一种新的冷冻框架，点击化学的再活化剂的开发使用乙酰胆碱酯酶-膦酸酯共轭物作为模板合成的三唑。除了肟辅助等离子体催化，新的肟和其他亲核试剂将被开发作为新的再活化剂在目标位点。这种化学方法还具有在合成-筛选范例中组合筛选中高通量的优点。将优化亲核试剂和亲核AChE组合，以增强对特定有害有机磷酸酯的治疗功效。因此，我们的方法将增强循环中有机磷酸酯的催化清除，并增强靶组织的再活化。

DESCRIPTION (provided by applicant): Our proposed project is directed to improving prophylaxis and therapy for organophosphate nerve agent organophosphate exposure through the design of mutant human acetylcholinesterases (AChEs), novel oximes and related reactivating nucleophiles. This strategy of "oxime-assisted catalysis" modifies AChE such that, when placed in the circulation, the oxime and AChE become a catalytic, rather than a stoichiometric, scavenger of organophosphates. Proof of principle has already been established for hydrolysis of a series of organophosphates, and we will refine AChE mutations and oxime structure to enhance catalytic rates for hydrolysis and retention in plasma space. Since oxime therapy, 2-PAM and HI-6, also reactivates inhibited AChE at the target site and the therapeutic benefits of long term oxime therapy have become fully appreciated recently, we propose to design new reactivators based on contemporary knowledge of AChE structure to which we and other groups have contributed to over the past two decades. This approach considers impaction of the active center gorge and angle of access of the oxime as limiting constraints in the design strategy. Moreover, the UCSD and TSRI groups have applied a novel freeze-frame, click chemistry to the development of reactivating agents using AChE-phosphonate conjugates as the template for synthesis of the triazoles. In addition to oxime assisted catalysis in plasma, new oximes and other nucleophiles will be developed as novel reactivating agents at the target site. This chemistry also enjoys the advantage of combinatorial screening for medium to high throughput in the synthesis-screening paradigm. Nucleophiles and nucleophile AChE combinations will be optimized for enhancing therapeutic efficacy to the particular offending organophosphate. Hence, our approach will both augment catalytic scavenging of organophosphates in the circulation and enhance reactivation at the target tissues.