Crystal structure of a Baeyer-Villiger monooxygenase
Crystal structure of a Baeyer-Villiger monooxygenase
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DOI：
10.1073/pnas.0404538101
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发表时间：
2004-09-07
影响因子：
11.1
通讯作者：
Mattevi, A
中科院分区：
文献类型：
--
作者：
Malito, E;Alfieri, A;Mattevi, A
含黄素的Baeyer-Villiger单加氧酶利用NADPH和分子氧催化氧原子插入羰基底物的碳-碳键。由于Baeyer-Villiger反应在合成有机化学中的广泛应用，这些酶可以潜在地用于各种生物催化应用中。这些酶的催化活性涉及两个关键中间体的形成：由还原的黄素与分子氧反应产生的黄素过氧化物和由黄素过氧化物攻击被氧化的底物产生的“Criegee”中间体。苯丙酮单加氧酶是嗜热菌Thermobifida fusca的一种Baeyer-Villiger单加氧酶，其晶体结构具有类似于二硫化物氧化还原酶的双结构域结构。活性位点位于结构域界面的裂缝中。精氨酸残基位于黄素环上方，位置适合于稳定带负电荷的黄素过氧化物和Criegee中间体。该氨基酸残基被预测存在于两个位置;在晶体结构中发现的“IN”位置和允许NADPH接近黄素以还原辅因子的“OUT”位置。域旋转提出了催化所涉及的构象变化。结构研究突出了这类黄素酶的功能复杂性，其协调三种底物（分子氧、NADPH和苯丙酮）在黄素辅因子附近的结合，形成两种不同的催化中间体。
Flavin-containing Baeyer-Villiger monooxygenases employ NADPH and molecular oxygen to catalyze the insertion of an oxygen atom into a carbon-carbon bond of a carbonylic substrate. These enzymes can potentially be exploited in a variety of biocatalytic applications given the wide use of Baeyer-Villiger reactions in synthetic organic chemistry. The catalytic activity of these enzymes involves the formation of two crucial intermediates: a flavin peroxide generated by the reaction of the reduced flavin with molecular oxygen and the "Criegee" intermediate resulting from the attack of the flavin peroxide onto the substrate that is being oxygenated. The crystal structure of phenylacetone monooxygenase, a Baeyer-Villiger monooxygenase from the thermophilic bacterium Thermobifida fusca, exhibits a two-domain architecture resembling that of the disulfide oxidoreductases. The active site is located in a cleft at the domain interface. An arginine residue lays above the flavin ring in a position suited to stabilize the negatively charged flavin-peroxide and Criegee intermediates. This amino acid residue is predicted to exist in two positions; the "IN" position found in the crystal structure and an "OUT" position that allows NADPH to approach the flavin to reduce the cofactor. Domain rotations are proposed to bring about the conformational changes involved in catalysis. The structural studies highlight the functional complexity of this class of flavoenzymes, which coordinate the binding of three substrates (molecular oxygen, NADPH, and phenylacetone) in proximity of the flavin cofactor with formation of two distinct catalytic intermediates.