Comparative molecular modeling of Anopheles gambiae CYP6Z1, a mosquito P450 capable of metabolizing DDT
Comparative molecular modeling of Anopheles gambiae CYP6Z1, a mosquito P450 capable of metabolizing DDT
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DOI：
10.1073/pnas.0709249105
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发表时间：
2008-07-01
影响因子：
11.1
通讯作者：
Schuler, Mary A.
中科院分区：
文献类型：
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作者：
Chiu, Ting-Lan;Wen, Zhimou;Schuler, Mary A.
疟疾控制面临的挑战之一是获得在蚊子身上形成的杀虫剂抗药性，蚊子是这种疾病的媒介。冈比亚按蚊是非洲疟疾寄生虫恶性疟原虫的主要蚊媒，多年来对狄氏剂、1，1-双(对氯苯基)-2，2，2-三氯乙烷(DDT)和拟除虫菊酯等杀虫剂产生了抗药性。以前的微阵列研究使用的是230An的片段。冈比亚病毒的5个P450基因座，包括CYP4C27、CYP4H15、CYP6Z1、CYP6Z2和CYP12F1，在耐DDT的Zan/U品系中的表达显著高于DDT敏感的Kisumu品系。为了预测CYP6Z1和CYP6Z2蛋白是否可能潜在地代谢DDT，我们建立了这两种蛋白的分子模型，并将其与没有DDT的分子模型进行了比较。这一比较表明，尽管这两个CYP6Z蛋白具有很高的序列同源性，但它们的代谢谱可能与较大的催化位点(可能参与DDT代谢)和较受限制的CYP6Z2(不可能代谢DDT)的催化位点有很大不同。这些蛋白质的异源表达证实了这些预测：只有CYP6Z1能够代谢DDT。这些模型的重叠表明，SRS1主链的微小差异以及SRS2和SRS4的侧链变化是导致它们的催化部位体积和DDT代谢能力显著不同的原因。这些数据确定了CYP6Z1是旨在灭活这种疟疾蚊子自然种群中杀虫剂代谢P450的抑制剂设计的一个重要目标。
One of the challenges faced in malarial control is the acquisition of insecticide resistance that has developed in mosquitoes that are vectors for this disease. Anopheles gambiae, which has been the major mosquito vector of the malaria parasite Plasmodium falciparum in Africa, has over the years developed resistance to insecticides including dieldrin, 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane (DDT), and pyrethroids. Previous microarray studies using fragments of 230An. gambiae genes identified five P450 loci, including CYP4C27, CYP4H15, CYP6Z1, CYP6Z2, and CYP12F1, that showed significantly higher expression in the DDT-resistant ZAN/U strain compared with the DDT-susceptible Kisumu strain. To predict whether either of the CYP6Z1 and CYP6Z2 proteins might potentially metabolize DDT, we generated and compared molecular models of these two proteins with and without DDT docked in their catalytic sites. This comparison indicated that, although these two CYP6Z proteins share high sequence identity, their metabolic profiles were likely to differ dramatically from the larger catalytic site of CYP6Z1, potentially involved in DDT metabolism, and the more constrained catalytic site of CYP6Z2, not likely to metabolize DDT. Heterologous expressions of these proteins have corroborated these predictions: only CYP6Z1 is capable of metabolizing DDT. Overlays of these models indicate that slight differences in the backbone of SRS1 and variations of side chains in SRS2 and SRS4 account for the significant differences in their catalytic site volumes and DDT-metabolic capacities. These data identify CYP6Z1 as one important target for inhibitor design aimed at inactivating insecticide-metabolizing P450s in natural populations of this malarial mosquito.