Abstract：
It is established that organophosphorus pesticide (OPP) toxicity results from modification of amino acids in active sites of target proteins. OPPs can also modify unrelated target proteins such as histones and such covalent histone modifications can alter DNA-binding properties and lead to aberrant gene expression. In the present study, we report on non-enzymatic covalent modifications of calf thymus histones adducted to selected OPPs and organophosphate flame retardants (OPFRs) in vitro using a bottom-up proteomics method approach. Histones were not found to form detectable adducts with the two tested OPFRs but were avidly modified by a few of the seven OPPs that were tested in vitro. Dimethyl phosphate (or diethyl phosphate) adducts were identified on Tyr, Lys and Ser residues. Most of the dialkyl phosphate adducts were identified on Tyr residues. Methyl and ethyl modified histones were also detected. Eleven amino residues in histones showed non-enzymatic covalent methylation by exposure of dichlorvos and malathion. Our bottom-up proteomics approach showing histone-OPP adduct formation warrants future studies on the underlying mechanism of chronic illness from exposure to OPPs.
摘要：
已确定有机磷农药（OPP）毒性是由靶蛋白活性位点中氨基酸的修饰引起的。OPP还可以修饰不相关的靶蛋白如组蛋白,并且这种共价组蛋白修饰可以改变DNA结合特性并导致异常的基因表达。在本研究中,我们报道了使用自下而上的蛋白质组学方法在体外检测小牛胸腺组蛋白与选定的OPP和有机磷酸酯阻燃剂（OPFRs）的非酶共价修饰。未发现组蛋白与两个测试的OPFR形成可检测的加合物，但被体外测试的七个OPP中的一些修饰。在Tyr上鉴定出磷酸二甲酯（或磷酸二乙酯）加合物，Lys和Ser残留物。大多数磷酸二烷基酯加合物在Tyr残基上被鉴定。还检测到甲基和乙基修饰的组蛋白。通过暴露敌敌畏和马拉硫磷，组蛋白中的11个氨基酸残基显示出非酶共价甲基化。我们的自下而上的蛋白质组学方法显示了组蛋白-OPP加合物的形成，值得未来对暴露于OPP的慢性疾病的潜在机制进行研究。
