Zhang Libin, Baker Stefanie L, Murata Hironobu, Harris Nicholas, Ji Weihang, Amitai Gabriel, Matyjaszewski Krzysztof, Russell Alan J
Center for Polymer-Based Protein Engineering Carnegie Mellon University 5000 Forbes Avenue Pittsburgh PA 15213 USA.
Department of Biomedical Engineering Carnegie Mellon University 5000 Forbes Avenue Pittsburgh PA 15213 USA.
Adv Sci (Weinh). 2019 Nov 13;7(1):1901904. doi: 10.1002/advs.201901904. eCollection 2020 Jan.
Organophosphate nerve agents rapidly inhibit cholinesterases thereby destroying the ability to sustain life. Strong nucleophiles, such as oximes, have been used as therapeutic reactivators of cholinesterase-organophosphate complexes, but suffer from short half-lives and limited efficacy across the broad spectrum of organophosphate nerve agents. Cholinesterases have been used as long-lived therapeutic bioscavengers for unreacted organophosphates with limited success because they react with organophosphate nerve agents with one-to-one stoichiometries. The chemical power of nucleophilic reactivators is coupled to long-lived bioscavengers by designing and synthesizing cholinesterase-polymer-oxime conjugates using atom transfer radical polymerization and azide-alkyne "click" chemistry. Detailed kinetic studies show that butyrylcholinesterase-polymer-oxime activity is dependent on the electrostatic properties of the polymers and the amount of oxime within the conjugate. The covalent coupling of oxime-containing polymers to the surface of butyrylcholinesterase slows the rate of inactivation of paraoxon, a model nerve agent. Furthermore, when the enzyme is covalently inhibited by paraoxon, the covalently attached oxime induced inter- and intramolecular reactivation. Intramolecular reactivation will open the door to the generation of a new class of nerve agent scavengers that couple the speed and selectivity of biology to the ruggedness and simplicity of synthetic chemicals.
有机磷酸酯类神经毒剂能迅速抑制胆碱酯酶，从而破坏维持生命的能力。强亲核试剂，如肟类，已被用作胆碱酯酶 - 有机磷酸酯复合物的治疗性重活化剂，但存在半衰期短以及对广谱有机磷酸酯类神经毒剂疗效有限的问题。胆碱酯酶曾被用作未反应有机磷酸酯的长效治疗性生物清除剂，但因它们与有机磷酸酯类神经毒剂以一对一化学计量比反应，效果有限。通过使用原子转移自由基聚合和叠氮 - 炔烃“点击”化学设计并合成胆碱酯酶 - 聚合物 - 肟共轭物，将亲核重活化剂的化学作用与长效生物清除剂相结合。详细的动力学研究表明，丁酰胆碱酯酶 - 聚合物 - 肟的活性取决于聚合物的静电性质以及共轭物中肟的含量。含肟聚合物与丁酰胆碱酯酶表面的共价偶联减缓了对氧磷（一种典型神经毒剂）的失活速率。此外，当该酶被对氧磷共价抑制时，共价连接的肟会诱导分子间和分子内重活化。分子内重活化将为生成一类新型神经毒剂清除剂打开大门，这类清除剂将生物学的速度和选择性与合成化学品的耐用性和简易性结合起来。
