Structures of cytochrome P450 2B4 complexed with the antiplatelet drugs ticlopidine and clopidogrel .
Structures of cytochrome P450 2B4 complexed with the antiplatelet drugs ticlopidine and clopidogrel .
复制标题
DOI：
10.1021/bi100914z
复制
发表时间：
2010-10-12
期刊：
影响因子：
2.9
通讯作者：
Halpert, James R.
中科院分区：
文献类型：
--
作者：
Gay, Sean C.;Roberts, Arthur G.;Maekawa, Keiko;Talakad, Jyothi C.;Hong, Wen-Xu;Zhang, Qinghai;Stout, C. David;Halpert, James R.
先前的兔细胞色素 P450 2B4 (2B4) 与各种咪唑复合物的 X 射线晶体结构已经证明，根据占据活性位点的抑制剂的大小，酶构象明显不同。在这项研究中，用抗血小板药物氯吡格雷和噻氯匹定解析了2B4的结构，预计它们在结合袋中具有更大的运动自由度。噻氯匹定可以建模为两个不同方向的电子密度图，这两个方向都与其他哺乳动物 P450 酶收集的代谢数据一致。配体对接和血红素诱导的药物质子核磁共振弛豫结果表明，噻氯匹定优先取向最靠近血红素的氯苯基。由于其立体中心，氯吡格雷更容易适应电子密度并表现出单一方向，将氯苯环指向血红素。两种复合物的 Cα 迹线彼此对齐得很好，并显示出紧凑、封闭的结构，类似于之前用小分子抑制剂 4-(4-氯苯基)咪唑和 1-(4-氯苯基)咪唑解析的两个 2B4 结构中观察到的构象。 2B4 活性位点能够通过仅移动少量侧链来容纳小配体，这表明配体重新定向比蛋白质构象变化更有利于这些相似大小分子的结合。调整活性位点的蛋白质构象和配体方向使 2B4 能够灵活地结合最广泛的分子，同时在能量上也有利。
Prior X-ray crystal structures of rabbit cytochrome P450 2B4 (2B4) in complex with various imidazoles have demonstrated markedly different enzyme conformations depending on the size of the inhibitor occupying the active site. In this study, structures of 2B4 were solved with the antiplatelet drugs clopidogrel and ticlopidine, which were expected to have greater freedom of movement in the binding pocket. Ticlopidine could be modeled into the electron density maps in two distinct orientations, both of which are consistent with metabolic data gathered with other mammalian P450 enzymes. Results of ligand docking and heme-induced NMR relaxation of drug protons showed that ticlopidine was preferentially oriented with the chlorophenyl group closest to the heme. Because of its stereocenter, clopidogrel was easier to fit in the electron density and exhibited a single orientation, which points the chlorophenyl ring toward the heme. The Cα traces of both complexes aligned very well to each other and revealed a compact, closed structure that resembles the conformation observed in two previously solved 2B4 structures with the small molecule inhibitors 4-(4-chlorophenyl)imidazole and 1-(4-chlorophenyl)imidazole. The 2B4 active site is able to accommodate small ligands by moving only a small number of side chains, suggesting that ligand reorientation is energetically favored over protein conformational changes for binding of these similar sized molecules. Adjusting both protein conformation and ligand orientation in the active site gives 2B4 the flexibility to bind to the widest range of molecules, while also being energetically favorable.
登录
查看更多内容
DOI：
10.1107/s0108767308018503
发表时间：
2008-09-01
影响因子：
1.8
作者：
Caliandro, Rocco;Carrozzini, Benedetta;Siliqi, Dritan
通讯作者：
Siliqi, Dritan
影响因子：
6.7
作者：
Donahue, SR;Flockhart, DA;Ko, JW
通讯作者：
Ko, JW
影响因子：
3.4
作者：
Constantine, KL
通讯作者：
Constantine, KL
影响因子：
3.9
作者：
Dalvie, DK;O'Connell, TN
通讯作者：
O'Connell, TN
影响因子：
2.9
作者：
Hummel, MA;Gannett, PM;Tracy, TS
通讯作者：
Tracy, TS