Mapping of the Allosteric Site in Cholesterol Hydroxylase CYP46A1 for Efavirenz, a Drug That Stimulates Enzyme Activity
Mapping of the Allosteric Site in Cholesterol Hydroxylase CYP46A1 for Efavirenz, a Drug That Stimulates Enzyme Activity
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DOI：
10.1074/jbc.m116.723577
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发表时间：
2016-05-27
影响因子：
4.8
通讯作者：
Pikuleva, Irina A.
中科院分区：
文献类型：
--
作者：
Anderson, Kyle W.;Mast, Natalia;Pikuleva, Irina A.
细胞色素P450 46 A1（CYP 46 A1）是一种微粒体酶和胆固醇24-羟化酶，控制胆固醇从大脑中消除。这种P450也是阿尔茨海默病的潜在靶点，因为它可以被一些上市药物激活，例如抗HIV药物依法韦仑。以前，我们认为药物通过结合到细胞溶质蛋白表面上的位点来变构激活CYP 46 A1，该位点不同于面向膜的酶活性位点。在这里，我们通过结合氢-氘交换与MS、计算建模、定点诱变和CYP 46 A1晶体结构分析，确定了CYP 46 A1上依法韦仑的变构位点。我们还绘制了CYP 46 A1氧化还原伴侣氧化还原酶的结合区域，发现变构和氧化还原伴侣结合位点共享一个共同的边界。在此基础上，我们提出了CYP 46 A1变构的机制和从P450变构位点到活性位点的信号传递途径。
Cytochrome P450 46A1 (CYP46A1) is a microsomal enzyme and cholesterol 24-hydroxylase that controls cholesterol elimination from the brain. This P450 is also a potential target for Alzheimer disease because it can be activated pharmacologically by some marketed drugs, as exemplified by efavirenz, the anti-HIV medication. Previously, we suggested that pharmaceuticals activate CYP46A1 allosterically through binding to a site on the cytosolic protein surface, which is different from the enzyme active site facing the membrane. Here we identified this allosteric site for efavirenz on CYP46A1 by using a combination of hydrogen-deuterium exchange coupled to MS, computational modeling, site-directed mutagenesis, and analysis of the CYP46A1 crystal structure. We also mapped the binding region for the CYP46A1 redox partner oxidoreductase and found that the allosteric and redox partner binding sites share a common border. On the basis of the data obtained, we propose the mechanism of CYP46A1 allostery and the pathway for the signal transmission from the P450 allosteric site to the active site.