Structural insights from a P450 Carrier Protein complex reveal how specificity is achieved in the P450Biol ACP complex
Structural insights from a P450 Carrier Protein complex reveal how specificity is achieved in the P450Biol ACP complex
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DOI：
10.1073/pnas.0805983105
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发表时间：
2008-10-14
影响因子：
11.1
通讯作者：
Schlichting, Ilme
中科院分区：
文献类型：
--
作者：
Cryle, Max J.;Schlichting, Ilme
来自枯草芽孢杆菌生物素操纵子的细胞色素P450(Biol)(CYP107H1)通过与酰基载体蛋白(ACP)相连的脂肪酸的多步氧化裂解形成七碳二元酸。P450Biol与三种不同长度的脂肪酰基-ACP(EscherichiaColi)配体形成的络合物的晶体结构表明，P450(Biol)与脂肪酸结合，从而迫使活性中心血红素上方的碳链形成U形。这就定位了C7和C8碳的氧化，在血红素之外有一个巨大的额外的空腔，以容纳脂肪酸的甲基末端，超出了裂解位置。这些结构解释了在实验中观察到的在游离脂肪酸的羟化和裂解中缺乏立体和区域特异性的原因。P450(Biol)-ACP复合体是迄今为止唯一具有结构特征的P450载体蛋白质复合体，这使得建立了万古霉素生物合成的P450 OxyB与其载体蛋白结合底物相互作用的模型。
Cytochrome P450(Biol)(CYP107H1) from the biotin operon of Bacillus subtilis forms a seven-carbon diacid through a multistep oxidative cleavage of a fatty acid linked to acyl carrier protein (ACP). Crystal structures of P450Biol in complex with three different length fatty acyl-ACP (Escherichia coli) ligands show that P450(Biol) binds the fatty acid such as to force the carbon chain into a U-shape above the active site heme. This positions the C7 and C8 carbons for oxidation, with a large additional cavity extending beyond the heme to accommodate the methyl termini of fatty acids beyond the site of cleavage. The structures explain the experimentally observed lack of stereo- and regiospecificity in the hydroxylation and cleavage of free fatty acids. The P450(Biol)-ACP complexes represent the only structurally characterized P450-carrier protein complexes to date, which has allowed the generation of a model of the interaction of the vancomycin biosynthetic P450 OxyB with its proposed carrier protein bound substrate.