Oxime-assisted Acetylcholinesterase Catalytic Scavengers of Organophosphates That Resist Aging
Oxime-assisted Acetylcholinesterase Catalytic Scavengers of Organophosphates That Resist Aging
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DOI：
10.1074/jbc.m111.264739
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发表时间：
2011-08-26
影响因子：
4.8
通讯作者：
Taylor, Palmer
中科院分区：
文献类型：
--
作者：
Cochran, Rory;Kalisiak, Jaroslaw;Taylor, Palmer
胆碱酯酶，乙酰胆碱酯酶(AChE)和丁酰胆碱酯酶，是有机磷(OPs)的主要靶标。暴露于有机磷农药可导致严重的心血管并发症、呼吸损害和死亡。目前对抗OP中毒的治疗方法包括使用肟类复活剂(2-PAM、奥比定、TMB4或HI-6)与阿托品联合使用，有时还使用抗惊厥药物。丁酰胆碱酯酶作为生物清除剂在血浆中使用，也显示出疗效，但受到其严格的化学计量清除、缓慢的再激活和老化倾向的限制。在这里，我们表征了10个人(H)乙酰胆碱酯酶突变体，当与一种肟类结合时，可以引起梭曼结合物的催化重新激活和抗老化。对于最有效的人类AChE突变体Y337A/F338A，我们发现当用HI-6(1-(2‘-hydroxyiminomethyl-1’-pyridinium)-3-(4‘-carbamoyl-1-pyridinium)).重新激活时，与野生型HAChE相比，几种OP-HAChE偶联物的复活率更高此外，我们询问了一个840个成员的新的肟文库，用于重新激活Y337A/F338A HAChE-OP偶联物，以描述最有效的用于催化生物清除的肟突变酶对。Y337A突变在受空间影响的活性中心峡谷内增加了对肟类的可及性，与F338A突变的抗老化能力相结合，为易老化的烷基磷酸抑制剂提供了更多的底物多样性。
The cholinesterases, acetylcholinesterase (AChE) and butyrylcholinesterase, are primary targets of organophosphates (OPs). Exposure to OPs can lead to serious cardiovascular complications, respiratory compromise, and death. Current therapy to combat OP poisoning involves an oxime reactivator (2-PAM, obidoxime, TMB4, or HI-6) combined with atropine and on occasion an anticonvulsant. Butyrylcholinesterase, administered in the plasma compartment as a bio-scavenger, has also shown efficacy but is limited by its strict stoichiometric scavenging, slow reactivation, and a propensity for aging. Here, we characterize 10 human (h) AChE mutants that, when coupled with an oxime, give rise to catalytic reactivation and aging resistance of the soman conjugate. With the most efficient human AChE mutant Y337A/F338A, we show enhanced reactivation rates for several OP-hAChE conjugates compared with wild-type hAChE when reactivated with HI-6 (1-(2'-hydroxyiminomethyl-1'-pyridinium)-3-(4'-carbamoyl-1-pyridinium)). In addition, we interrogated an 840-member novel oxime library for reactivation of Y337A/F338A hAChE-OP conjugates to delineate the most efficient oxime-mutant enzyme pairs for catalytic bio-scavenging. Combining the increased accessibility of the Y337A mutation to oximes within the space-impacted active center gorge with the aging resistance of the F338A mutation provides increased substrate diversity in scavenging potential for aging-prone alkyl phosphate inhibitors.