Oxime-Assisted Catalysis of Organophosphates and Reactivation of AChE

描述（由申请人提供）：我们提议的项目旨在通过设计突变的人类乙酰胆碱酯酶（AChEs），新型肟和相关的再激活亲核试剂来改善有机磷神经毒剂暴露的预防和治疗。这种“肟辅助催化”的策略改变了乙酰氨基甲酸酯，当将其置于循环中时，肟和乙酰氨基甲酸酯成为有机磷酸盐的催化剂，而不是化学计量的清除剂。已经建立了一系列有机磷酸盐水解的原理证明，我们将改进AChE突变和肟结构，以提高水解和在等离子体空间中保留的催化速率。由于肟治疗，2-PAM和HI-6也能在靶点重新激活被抑制的AChE，并且长期肟治疗的治疗益处最近已经得到充分认识，我们建议基于我们和其他团队在过去二十年中对AChE结构的当代知识设计新的再激活剂。该方法在设计策略中考虑了活动中心峡谷的影响和肟的进入角度作为限制条件。此外，UCSD和TSRI小组已经应用了一种新的定格，点击化学来开发以乙酰膦酸酯偶联物为模板的再活化剂来合成三唑。除了肟在血浆中的辅助催化外，新的肟和其他亲核试剂将被开发作为靶部位的新型再活化剂。在合成筛选范例中，该化学还享有中到高通量组合筛选的优势。亲核试剂和亲核试剂AChE的组合将被优化，以提高对特定的有害有机磷酸盐的治疗效果。因此，我们的方法将增强循环中有机磷的催化清除和增强靶组织的再激活。

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.