Oxime-Assisted Catalysis of Organophosphates and Reactivation of AChE

描述(由申请人提供)：我们建议的项目旨在通过设计突变的人乙酰胆碱酯酶(AChs)、新的肟类和相关的重新激活的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“肟基辅助催化”的策略对乙酰胆碱酯酶进行了修饰，使其在进入循环后成为有机磷的催化剂，而不是化学计量比的清除剂。一系列有机磷的水解已经建立了原理证明，我们将完善AChE突变和肟结构，以提高催化水解和保留在等离子体空间的速度。由于2-PAM和HI-6这两种肟类药物也能使靶部位被抑制的AChE重新激活，而且最近人们已经充分认识到了长期使用肟类药物的治疗益处，我们建议根据当代对AChE结构的了解来设计新的复活剂，这是我们和其他研究小组在过去二十年中所做出的贡献。该方法在设计策略中考虑了主动中心峡谷的冲击作用和移动体的接触角作为极限约束。此外，UCSD和TSRI小组还应用了一种新的冷冻-点击化学方法来开发以AChE-膦酸酯偶合物为模板合成三唑类化合物的复活剂。除了在血浆中的肟类辅助催化外，新的肟类和其他亲核试剂将被开发为目标位置的新的再活化剂。在合成-筛选范式中，这种化学还享有中到高通量的组合筛选的优势。将优化亲核和亲核AChE组合，以提高对特定有害有机磷的治疗效果。因此，我们的方法将既增强循环中有机磷的催化清除，又增强目标组织的再激活。

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.