Department of Biochemical Sciences, Sapienza University of Rome and CNR Institute of Molecular Biology and Pathology, Piazzale A. Moro 5, Rome, Italy.
Biochemistry. 2010 Nov 2;49(43):9199-206. doi: 10.1021/bi101062v.
EryK is a bacterial cytochrome P450 that catalyzes the last hydroxylation occurring during the biosynthetic pathway of erythromycin A in Streptomyces erythraeus. We report the crystal structures of EryK in complex with two widely used azole inhibitors: ketoconazole and clotrimazole. Both of these ligands use their imidazole moiety to coordinate the heme iron of P450s. Nevertheless, because of the different chemical and structural properties of their N1-substituent group, ketoconazole and clotrimazole trap EryK, respectively, in a closed and in an open conformation that resemble the two structures previously described for the ligand-free EryK. Indeed, ligands induce a distortion of the internal helix I that affects the accessibility of the binding pocket by regulating the kink of the external helix G via a network of interactions that involves helix F. The data presented thus constitute an example of how a cytochrome P450 may be selectively trapped in different conformational states by inhibitors.
EryK 是一种细菌细胞色素 P450，它催化红霉素 A 生物合成途径中最后一步的羟化反应，发生在红色糖多孢菌中。我们报道了 EryK 与两种广泛使用的唑类抑制剂：酮康唑和克霉唑复合物的晶体结构。这两种配体都使用其咪唑部分来配位 P450 中的血红素铁。然而，由于它们的 N1-取代基的不同化学和结构性质，酮康唑和克霉唑分别将 EryK 捕获在类似于先前描述的两种无配体 EryK 结构的封闭和开放构象中。事实上，配体通过涉及 F 螺旋的相互作用网络调节外 G 螺旋的扭曲，从而导致内部 I 螺旋的扭曲，这影响了结合口袋的可及性。因此，所呈现的数据构成了一个例子，说明细胞色素 P450 如何通过抑制剂选择性地捕获不同的构象状态。
