Crystal structure of (+)-delta-cadinene synthase from Gossypium arboreum and evolutionary divergence of metal binding motifs for catalysis.
Crystal structure of (+)-delta-cadinene synthase from Gossypium arboreum and evolutionary divergence of metal binding motifs for catalysis.
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DOI：
10.1021/bi900483b
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发表时间：
2009-07-07
期刊：
影响因子：
2.9
通讯作者：
Christianson, David W.
中科院分区：
文献类型：
--
作者：
Gennadios, Heather A.;Gonzalez, Veronica;Di Costanzo, Luigi;Li, Amang;Yu, Fanglei;Miller, David J.;Allemann, Rudolf K.;Christianson, David W.
(+)-δ-Cadinene合成酶是一种倍半萜环化酶，在棉酚生物合成的第一步催化法尼基二磷酸的环化反应，棉酚是一种植物保卫素，用于保护植物免受细菌和真菌的侵袭。在这里，我们报道了未配位的DCs的X射线晶体结构，以及它与三个可能的镁离子和底物类似物抑制剂2-氟阿尼基二磷酸(2F-FPP)的2.75？分辨率的配合物的结构。这些结构揭示了不寻常的特征，适应了底物结合和催化所需的三核金属簇。和其他萜类环酶一样，DCs在D螺旋上含有一个特征的富含天冬氨酸的基序D307DTYD311，它与镁2+A和镁2+C相互作用。然而，在萜类环化酶中，它似乎是独一无二的，因为它不包含H螺旋上的“NSE/DTE”基序，该基序专门螯合镁2+B，这通常被发现为签名序列(N，D)D(L，I，V)X(S，T)XXXE(粗体表示镁2+B配体)。相反，DC包含第二个富含天冬氨酸的基序D451DVAE455，与镁离子B相互作用。在这方面，DCS更类似于异戊二烯链伸长酶法尼基二磷酸合成酶，它也包含两个富含天冬氨酸的基序，而不是更大的萜类环酶家族。然而，DCS2F-FPP复合体的结构表明，尽管有不同的镁离子结合基序，但三核镁簇的结构与其他萜类环酶的结构基本相似。对D307DTYD311和D451DVAE455片段丙氨酸替换的DC突变体的分析揭示了这些片段对催化的贡献。
(+)-δ-Cadinene synthase (DCS) from Gossypium arboreum (tree cotton) is a sesquiterpene cyclase that catalyzes the cyclization of farnesyl diphosphate in the first committed step of the biosynthesis of gossypol, a phytoalexin that defends the plant from bacterial and fungal pathogens. Here, we report the X-ray crystal structure of unliganded DCS at 2.4 Å resolution and the structure of its complex with three putative Mg2+ ions and the substrate analogue inhibitor 2-fluorofarnesyl diphosphate (2F-FPP) at 2.75 Å resolution. These structures illuminate unusual features that accommodate the trinuclear metal cluster required for substrate binding and catalysis. Like other terpenoid cyclases, DCS contains a characteristic aspartate-rich motif D307DTYD311 on helix D that interacts with Mg2+A and Mg2+C. However, DCS appears to be unique among terpenoid cyclases in that it does not contain the “NSE/DTE” motif on helix H that specifically chelates Mg2+B, which is usually found as the signature sequence (N, D)D(L, I, V)X(S, T)XXXE (boldface indicates Mg2+B ligands). Instead, DCS contains a second aspartate-rich motif, D451DVAE455, that interacts with Mg2+B. In this regard, DCS is more similar to the isoprenoid chain elongation enzyme farnesyl diphosphate synthase, which also contains two aspartate-rich motifs, rather than the greater family of terpenoid cyclases. Nevertheless, the structure of the DCS-2F-FPP complex shows that the structure of the trinuclear magnesium cluster is generally similar to that of other terpenoid cyclases despite the alternative Mg2+B-binding motif. Analyses of DCS mutants with alanine substitutions in the D307DTYD311 and D451DVAE455 segments reveal the contributions of these segments to catalysis.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
15
作者：
Calvert, MJ;Ashton, PR;Allemann, RK
通讯作者：
Allemann, RK
影响因子：
4.8
作者：
Hosfield, DJ;Zhang, YM;Finn, J
通讯作者：
Finn, J
DOI：
10.1107/s0907444998003254
发表时间：
1998-09-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY
影响因子：
--
作者：
Brunger, AT;Adams, PD;Warren, GL
通讯作者：
Warren, GL
影响因子：
11.6
作者：
Kampranis, Sotirios C.;Ioannidis, Daphne;Johnson, Christopher B.
通讯作者：
Johnson, Christopher B.