Modulation of substrate binding to naphthalene 1,2-dioxygenase by rieske cluster reduction/oxidation.
Modulation of substrate binding to naphthalene 1,2-dioxygenase by rieske cluster reduction/oxidation.
复制标题
通过 rieske 簇还原/氧化调节底物与萘 1,2-双加氧酶的结合。
DOI：
10.1021/ja028781m
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发表时间：
2003
影响因子：
15
通讯作者：
Hoffman,BrianM
中科院分区：
文献类型：
--
作者：
Yang,Tran-Chin;Wolfe,MattD;Neibergall,MatthewB;Mekmouche,Yasmina;Lipscomb,JohnD;Hoffman,BrianM
萘1，2-双加氧酶的加氧酶活性部位含有一个Rieske Fe−S簇和一个单核非血红素铁，它们是由(α)3结构中不同的αβ亚基贡献的。该酶催化芳香族底物的二羟基化反应，以及许多其他不定氧化反应。高分辨率的Mims2H-Endor谱记录了NDO与8-萘和d2-萘结合的非铁中心；收集了具有Rieske双铁中心的酶的氧化和还原状态的光谱。对于每一种底物，都检测到了来自附近底物氘核的锐利的四重态Endor图案。对用1，4-二肼基萘制备的样品的检测表明，该信号来自d1。ENDOR数据将d1放置在距单核Fe约4.4？处，且Fe−D向量大致沿Fe−N(O)方向。由于氧结合和后续催化需要Rieske簇的还原，因此考察了其氧化态对底物结合的影响。NdO-−-萘络合物的光谱显示出两种不同的结合构象，它们的相对布居数随Rieske簇氧化状态的变化而变化。这种转变，以及它所暗示的构象偶联，可能是Rieske芳香双加氧酶氧气门控和氧气反应性的关键。
The active site of the oxygenase component of naphthalene 1,2-dioxygenase (NDO) contains a Rieske Fe−S cluster and a mononuclear non-heme iron, which are contributed by different α-subunits in the (αβ)3structure. The enzyme catalyzescis-dihydroxylation of aromatic substrates in addition to numerous other adventitious oxidation reactions. High-resolution Mims2H-ENDOR spectra have been recorded for the NO-ferrous center of NDO bound withd8-naphthalene andd2-naphthalene; spectra were collected for the enzyme with the Rieske diiron center both in its oxidized and in its reduced states. A sharp quartet ENDOR pattern from a nearby deuteron of substrate was detected for each substrate. Examination of the sample prepared with 1,4-dideutero-naphthalene shows that the signal arises from D1. The ENDOR data place D1 at a distance of ca. 4.4 Å from the mononuclear Fe and with the Fe−D vector being roughly along the Fe−N(O) direction. Because reduction of the Rieske cluster is required for O2binding and subsequent catalysis, the effect of its oxidation state on substrate binding was examined. The spectra from the NDO−naphthalene complex reveal two different binding conformations, which change in relative population when the oxidation state of the Rieske cluster is changed. This shift, and the conformational coupling it implies, may hold the key to both oxygen gating and oxygen reactivity for Rieske aromatic dioxygenases.