Juvenile hormone synthesis: "esterify then epoxidize" or "epoxidize then esterify"? Insights from the structural characterization of juvenile hormone acid methyltransferase.
Juvenile hormone synthesis: "esterify then epoxidize" or "epoxidize then esterify"? Insights from the structural characterization of juvenile hormone acid methyltransferase.
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DOI：
10.1016/j.ibmb.2010.12.008
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发表时间：
2011-04
影响因子：
3.8
通讯作者：
Turjanski, A. G.
中科院分区：
文献类型：
--
作者：
Defelipe, L. A.;Dolghih, E.;Roitberg, A. E.;Nouzova, M.;Mayoral, J. G.;Noriega, F. G.;Turjanski, A. G.
关键词：
保幼激素在昆虫变态和生殖过程中起着重要的调节作用。JH合成的最后两个步骤根据昆虫目而不同。在鳞翅目昆虫中，P450单加氧酶的环氧化作用先于保幼激素酸甲基转移酶（JHAMT）的酯化作用。在直翅目、网翅目、鞘翅目和双翅目中，甲基化之后是环氧化。我们研究的目的是深入了解JHAMT的底物识别的结构基础，作为了解这些途径的分歧的一种手段。采用同源模建方法构建埃及伊蚊JHAMT基因的结构。确定了底物结合位点，以及与甲基供体（S-腺苷甲硫氨酸）和底物甲基受体（法呢酸（FA）和保幼激素酸（JHA））的羧酸相互作用的残基。为了获得进一步的了解，我们生成了冈比亚按蚊、桑按蚊、黑腹果蝇和赤拟谷盗JHAMT的结构。建模结果进行了比较与以前的实验研究，使用重组蛋白，整个昆虫，咽侧体或组织提取物。计算研究有助于解释对（10 R）-JHA异构体的选择性和棕榈酸和月桂酸的活性降低。我们的研究结果的分析支持的假设，所有的昆虫JHAMT都能够识别FA和JHA作为基板。因此，甲基化/环氧化反应的顺序可能主要由环氧酶的底物特异性决定。在鳞翅目昆虫中，环氧酶可能比JHAMT对FA具有更高的亲和力，因此环氧化先于甲基化，而在大多数其他昆虫中，FA没有环氧化，而是酯化形成MF，然后环氧化为JH III。
Juvenile hormones (JHs) play key roles in regulating metamorphosis and reproduction in insects. The last two steps of JH synthesis diverge depending on the insect order. In Lepidoptera, epoxidation by a P450 monooxygenase precedes esterification by a juvenile hormone acid methyltransferase (JHAMT). In Orthoptera, Dictyoptera, Coleoptera and Diptera epoxidation follows methylation. The aim of our study was to gain insight into the structural basis of JHAMT’s substrate recognition as a means to understand the divergence of these pathways. Homology modeling was used to build the structure of Aedes aegypti JHAMT. The substrate binding site was identified, as well as the residues that interact with the methyl donor (S-adenosylmethionine) and the carboxylic acid of the substrate methyl acceptors, farnesoic acid (FA) and juvenile hormone acid (JHA). To gain further insight we generated the structures of Anopheles gambiae, Bombyx mori, Drosophila melanogaster and Tribolium castaneum JHAMTs. The modeling results were compared with previous experimental studies using recombinant proteins, whole insects, corpora allata or tissue extracts. The computational study helps explain the selectivity towards the (10R)-JHA isomer and the reduced activity for palmitic and lauric acids. The analysis of our results supports the hypothesis that all insect JHAMTs are able to recognize both FA and JHA as substrates. Therefore, the order of the methylation/epoxidation reactions may be primarily imposed by the epoxidase’s substrate specificity. In Lepidoptera, epoxidase might have higher affinity than JHAMT for FA, so epoxidation precedes methylation, while in most other insects there is no epoxidation of FA, but esterification of FA to form MF, followed by epoxidation to JH III.
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DOI：
10.1073/pnas.0909938106
发表时间：
2009-12-15
影响因子：
11.1
作者：
Mayoral, Jaime G.;Nouzova, Marcela;Noriega, Fernando G.
通讯作者：
Noriega, Fernando G.
影响因子：
5.6
作者：
Bower, MJ;Cohen, FE;Dunbrack, RL
通讯作者：
Dunbrack, RL
影响因子：
14.9
作者：
Poirot, O;O'Toole, E;Notredame, C
通讯作者：
Notredame, C
影响因子：
5.8
作者：
Larkin, M. A.;Blackshields, G.;Higgins, D. G.
通讯作者：
Higgins, D. G.
影响因子：
3
作者：
Morris, Garrett M.;Huey, Ruth;Lindstrom, William;Sanner, Michel F.;Belew, Richard K.;Goodsell, David S.;Olson, Arthur J.
通讯作者：
Olson, Arthur J.