玉米烯酮霉素降解相关内酯水解酶的催化机理研究及分子改造

Zearalenone (ZEN) is a kind of mycotoxin with estrogenic activity and is widespread in forages contaminated by molds. The contamination of ZEN causes huge loss to feed industry and livestock husbandry and even brings serious public health problems. Since neither chemicals nor physical absorption can remove mycotoxin effectively, development of the enzymic detoxification could offer an efficient method of removing ZEN decontamination. A lactonase ZHD101 which can degrade ZEN effectively is being widely studied. However, the reaction mechanisms aren’t clear now. In this study, we plan to resolve the crystal structures of ZHD101 in apo-form and in complex with two substrates, ZEN and β-ZOL. The key residues for activity and substrate specificity will be analyzed by using the structures. This study will elucidate the reaction mechanisms at molecular level and provide the theoretical guide for molecular engineering which contributes to the high potential ZEN hydrolase.

玉米烯酮霉素是一种具有雌激素活性的霉菌毒素，在被霉菌污染的作物饲料中广泛存在，造成饲料业和畜牧业的巨大损失，甚至引发严重的公共卫生问题。由于化学和物理的方法通常不能选择性的去除毒素，因此，开发高效的霉菌毒素降解酶是解决霉菌毒素污染问题的重要手段。内酯水解酶ZHD101是目前研究最广泛的玉米烯酮霉素降解酶，但催化反应机理尚不明确。本课题拟利用X光晶体学的手段，通过解析ZHD101及其与底物ZEN、β-ZOL的复合物结构，揭示其催化反应的机理，并考察结构中影响活力和底物专一性的重要氨基酸残基，为获得高效降解玉米烯酮毒素的内酯水解酶提供理论指导。

玉米赤霉烯酮是一种具有雌激素活性的霉菌毒素，在被霉菌污染的作物饲料中广泛存在，造成饲料业和畜牧业的巨大损失，甚至引发严重的公共卫生问题。来源于 Clonostachys rosea 的内酯水解酶ZHD是目前研究最广泛的玉米赤霉烯酮水解酶，能够降解玉米赤霉烯酮(ZEN)和其衍生物玉米赤霉烯醇(ZOL)，但催化反应机理尚不明确。本课题利用X光晶体学的手段，通过解析ZHD（ZHD101）及其与底物ZEN、β-ZOL的复合物结构，揭示了他们的催化反应机理，本课题进行基于结构的理性合理设计来突变内酯环周边酶的活性区附近的残基，提高了ZHD 对ZOL 的水解 活性，为获得高效降解玉米烯酮毒素的内酯水解酶提供理论指导。