Azole drugs trap cytochrome P450 EryK in alternative conformational states.
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.
Montemiglio
Linda Celeste
LC
Department of Biochemical Sciences, Sapienza University of Rome and CNR Institute of Molecular Biology and Pathology, Piazzale A. Moro 5, Rome, Italy.
Gianni
Stefano
S
Vallone
Beatrice
B
Savino
Carmelinda
C
D001393:Azoles / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D001426:Bacterial Proteins / Q000737:chemistry* / Q000187:drug effects; D020134:Catalytic Domain; D003022:Clotrimazole / Q000737:chemistry; D018360:Crystallography, X-Ray; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry* / Q000187:drug effects; D007654:Ketoconazole / Q000737:chemistry; D011487:Protein Conformation / Q000187:drug effects; D016930:Saccharopolyspora / Q000737:chemistry*
D001393:Azoles; D001426:Bacterial Proteins; D003577:Cytochrome P-450 Enzyme System; D003022:Clotrimazole; D007654:Ketoconazole