晶体结构的基质和基质模拟复合物protocatechuate 3 4-dioxygenase:内生Fe3 +配体位移响应衬底绑定。
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奥维尔,以至于JD,黑轮DH
晶体结构的基质和基质模拟复合物protocatechuate 3 4-dioxygenase:内生Fe3 +配体位移响应衬底绑定。
生物化学。1997年8月19日,36 (33):10052 - 66。
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9254600 (在PubMed]
- 文摘
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4-PCD Protocatechuate 3 4-dioxygenase(3)利用铁离子催化的芳环裂3,4-dihydroxybenzoate (PCA)合并的两个原子的分子氧产量beta-carboxy-cis, cis-muconate。厌氧的晶体结构3、4-PCD。PCA复杂,需氧复合物有两个杂环PCA类似物,2-hydroxyisonicotinic酸N-oxide(间接宾语)和6-hydroxynicotinic酸N-oxide (NNO)和三元配合物3,4-PCD.INO。CN和3,4-PCD。NNO。CN已经确定在2.1 - -2.2决议和改进r个因子在0.165和0.184之间。PCA,进气阀打开,NNO非常相似的形式,进行不对称螯合配合物与活性部位Fe3 +导致分离的内生轴tyrosinate Fe3 +配体,Tyr447 (147 beta)。从铁上映后,Tyr447被氢键稳定Tyr16(16α)和Asp413 (113 beta),形成一个小腔的顶部附近PCA的同样的债券。赤道Fe3 +协调网站在这个空腔是厌氧3,无人4-PCD。PCA复杂但坐标的溶剂分子3 4-PCD。伊诺和3,4-PCD。NNO复合物和CN - 3, 4-PCD.INO。CN和3,4-PCD.NNO。CN复合物。这表明一个O2模拟可以占领腔,表明亲电O2发起攻击PCA从这个网站。 Both the dissociation of the endogenous Tyr447 and the expansion of the iron coordination sphere are novel features of the 3,4-PCD. substrate complex which appear to play essential roles in the activation of substrate for O2 attack. Together, the structures presented here and in the preceding paper [Orville, A. M., Elango, N. , Lipscomb, J. D., & Ohlendorf, D. H. (1997) Biochemistry 36, 10039-10051] provide atomic models for several steps in the reaction cycle of 3,4-PCD and related Fe3+-containing dioxygenases.