Probing the role of amino acids in oxime-mediated reactivation of nerve agent-inhibited human acetylcholinesterase
Probing the role of amino acids in oxime-mediated reactivation of nerve agent-inhibited human acetylcholinesterase
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DOI：
10.1016/j.tiv.2014.11.001
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发表时间：
2015-03-01
影响因子：
3.2
通讯作者：
Saxena, Ashima
中科院分区：
文献类型：
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作者：
Chambers, Carolyn;Luo, Chunyuan;Saxena, Ashima
在这项研究中，我们利用定点突变来了解峡谷中的氨基酸在神经毒剂抑制的人(HU)乙酰胆碱酯酶(AChE)再激活过程中的作用。所研究的有机磷(OP)神经毒剂包括GA(Tabun)、GB(沙林)、GF(环沙林)、VX和VR。用2-PAM和MMB4、HI-6和HLO-7研究了再活化反应的动力学。二阶复活速率常数用于比较神经毒剂抑制的野生型(WT)和突变型酶的复活。Y72、Y124和W286残基在双吡啶的复活中起重要作用，而在单吡啶的复活中不起作用。Y124残基在HI-6和HLO-7的复活中起关键作用，而E202在所有的肟类复活中起重要作用。F295的残基被Leu取代，Y337的残基被Ala取代，这表明双吡啶肟类化合物MMB4、HI-6和HLO-7对F295和Y337的重新激活有促进作用，这可能是因为它提供了更多与肟相关的活性部位丝氨酸的OP部分。这些结果与以前用牛AChE观察到的结果相似，表明人和牛AChE在肟酶重新激活方面有显著的相似之处。爱思唯尔有限公司出版。
In this study, we employed site-directed mutagenesis to understand the role of amino acids in the gorge in oxime-induced reactivation of nerve agent-inhibited human (Hu) acetylcholinesterase (AChE). The organophosphorus (OP) nerve agents studied included GA (tabun), GB (sarin), GF (cyclosarin), VX, and VR. The kinetics of reactivation were examined using both the mono-pyridinium oxime 2-PAM and bis-pyridinium oximes MMB4, HI-6, and HLo-7. The second-order reactivation rate constants were used to compare reactivation of nerve agent-inhibited wild-type (WT) and mutant enzymes. Residues including Y72, Y124 and W286 were found to play important roles in reactivation by bis-pyridinium, but not by mono-pyridinium oximes. Residue Y124 also was found to play a key role in reactivation by HI-6 and HLo-7, while E202 was important for reactivation by all oximes. Residue substitutions of F295 by Leu and Y337 by Ala showed enhanced reactivation by bis-pyridinium oximes MMB4, HI-6, and HLo-7, possibly by providing more accessibility of the OP moiety associated at the active-site serine to the oxime. These results are similar to those observed previously with bovine AChE and demonstrate that there is significant similarity between human and bovine AChEs with regard to oxime reactivation. Published by Elsevier Ltd.