实验和理论计算应证玉米体中HBCD的选择性吸收和生物转化
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- 英文论文题名：Experimental and theoretical evidences for diastereomer-and enantiomer-specific accumulation and biotransformation of HBCD in maize
- 论文作者：黄红林 ; 王丹 ; 张淑贞
- 英文论文作者：Honglin Huang ; Dan Wang ; Shuzhen Zhang ; State Key Laboratory of Environmental Chemistry and Ecotoxicology ; Research Center for Eco-Environmental Sciences ; Chinese Academy of Sciences
- 年：2016
- 作者机构：中国科学院生态环境研究中心;
- 论文关键词：六溴环十二烷 ; 玉米 ; 吸收 ; 生物转化 ; 非对映体和对映异构体选择性
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第二十六分会：环境化学
- 语种：中文
- 分类号：X503.231;S513
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第二十六分会 ; 环境化学
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：1
- 文件大小：258k
- 原文格式：D
- 会议级别：全国
摘要
采用活体暴露实验研究了HBCD在玉米体内的生物累积、手性异构化和代谢。同时通过计算的方法表征了植物亚型酶与HBCD异构体的分子间相互作用。研究结果表明玉米根中(-)α-,(-)β-和(+)γ-HBCD的生物累积显著高于其对映体。观测到(+)/(-)β-和γ-HBCD向(-)α-HBCD的异构转化,其中(-)γ-HBCD最易发生异构化。在玉米体内检测到了HBCD-GSH加和物,脱一个或者两个溴的代谢产物PBCDs和TBCD,及其羟化和双羟化的代谢产物:OH-HBCDs和OH-PBCDs。玉米体内HBCD的脱溴和羟基化生物转化存在着对映体的显著差异。HBCD的三对对映体能够选择性进入玉米CYP和GST亚型酶CYP71C3v2、GST31的活性位点并与其键合。相对于各自的对映体对,(+)α-,(-)β-和(-)γ-HBCD更易与CYP71C3v2结合,而(-)α-,(-)β-和(+)γ-HBCD与GST31有更强的键合,这与(+)α-,(-)β-和(-)γ-HBCD更容易发生羟基化代谢,而(-)α-,(-)β-和(+)γ-HBCD更易手性异构化以及脱溴的实验结果一致。本研究结合活体暴露实验和理论计算证实了HBCD对映体在植物体中的选择性行为,加深了对HBCD环境过程的认识。
Diastereomer-and enantiomer-specific accumulation and biotransformation of hexabromocyclododecane(HBCD) in maize(Zea mays L.) were investigated.Molecular interactions of HBCD with plant isozymes were further characterized by homology modeling combined with molecular docking.The(-)α-,(-)β-and(+)γ-HBCDs accumulated significantly higher in maize than their corresponding antipodes.Bioisomerization from(+)/(-)-β-and γ-HBCDs to(-)α-HBCD was frequently observed,and(-)γ-HBCD was most easily converted.Mono-and di-hydroxyl HBCDs,debrominated metabolites of pentabromocyclododecenes(PBCDs) and tetrabromocyclododecenes(TBCDs),and HBCD-GSH adducts were detected in maize.Patterns of hydroxylated and debrominated metabolites were significantly different among HBCD diastereomers and enantiomers.Three pairs of HBCD enantiomers selectively bound into the active sites and interacted with specific residues of maize isozymes of CYP71C3v2 and GST31.(+)α-,(-)β-and(-)γ-HBCDs preferentially bound to CYP71C3v2,whereas(-)α-,(-)β-and(+)γ-HBCD had strong affinities to GST31,consistent with the experimental observations that(+)α-,(-)β-and(-)γ-HBCDs were more easily hydroxylated,and(-)α-,(-)β-and(+)γ-HBCDs were more easily isomerized and debrominated in maize compared to their enantiomeric pairs.This study for the first time provided both experimental and theoretical evidences for stereo-specific biotic processes of HBCD in maize.
Diastereomer-and enantiomer-specific accumulation and biotransformation of hexabromocyclododecane(HBCD) in maize(Zea mays L.) were investigated.Molecular interactions of HBCD with plant isozymes were further characterized by homology modeling combined with molecular docking.The(-)α-,(-)β-and(+)γ-HBCDs accumulated significantly higher in maize than their corresponding antipodes.Bioisomerization from(+)/(-)-β-and γ-HBCDs to(-)α-HBCD was frequently observed,and(-)γ-HBCD was most easily converted.Mono-and di-hydroxyl HBCDs,debrominated metabolites of pentabromocyclododecenes(PBCDs) and tetrabromocyclododecenes(TBCDs),and HBCD-GSH adducts were detected in maize.Patterns of hydroxylated and debrominated metabolites were significantly different among HBCD diastereomers and enantiomers.Three pairs of HBCD enantiomers selectively bound into the active sites and interacted with specific residues of maize isozymes of CYP71C3v2 and GST31.(+)α-,(-)β-and(-)γ-HBCDs preferentially bound to CYP71C3v2,whereas(-)α-,(-)β-and(+)γ-HBCD had strong affinities to GST31,consistent with the experimental observations that(+)α-,(-)β-and(-)γ-HBCDs were more easily hydroxylated,and(-)α-,(-)β-and(+)γ-HBCDs were more easily isomerized and debrominated in maize compared to their enantiomeric pairs.This study for the first time provided both experimental and theoretical evidences for stereo-specific biotic processes of HBCD in maize.
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