title: Structural analyses ofCandida albicanssterol 14α-demethylase complexed with azole drugs address the molecular basis of azole-mediated inhibition of fungal sterol biosynthesis.
abstract: With some advances in modern medicine (such as cancer chemotherapy, broad exposure to antibiotics, and immunosuppression), the incidence of opportunistic fungal pathogens such asCandida albicanshas increased. Cases of drug resistance among these pathogens have become more frequent, requiring the development of new drugs and a better understanding of the targeted enzymes. Sterol 14α-demethylase (CYP51) is a cytochrome P450 enzyme required for biosynthesis of sterols in eukaryotic cells and is the major target of clinical drugs for managing fungal pathogens, but some of the CYP51 key features important for rational drug design have remained obscure. We report the catalytic properties, ligand-binding profiles, and inhibition of enzymatic activity ofC. albicansCYP51 by clinical antifungal drugs that are used systemically (fluconazole, voriconazole, ketoconazole, itraconazole, and posaconazole) and topically (miconazole and clotrimazole) and by a tetrazole-based drug candidate, VT-1161 (oteseconazole: (R)-2-(2,4-difluorophenyl)-1,1-difluoro-3-(1H-tetrazol-1-yl)-1-(5-(4-(2,2,2-trifluoroethoxy)phenyl)pyridin-2-yl)propan-2-ol). Among the compounds tested, the first-line drug fluconazole was the weakest inhibitor, whereas posaconazole and VT-1161 were the strongest CYP51 inhibitors. We determined the X-ray structures ofC. albicansCYP51 complexes with posaconazole and VT-1161, providing a molecular mechanism for the potencies of these drugs, including the activity of VT-1161 againstCandida kruseiandCandida glabrata, pathogens that are intrinsically resistant to fluconazole. Our comparative structural analysis outlines phylum-specific CYP51 features that could direct future rational development of more efficient broad-spectrum antifungals.
authors.affiliation: From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
authors.forename: Tatiana Y
authors.initials: TY
authors.lastname: Hargrove
authors.affiliation: From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
authors.forename: Laura
authors.initials: L
authors.lastname: Friggeri
authors.affiliation: the Synchrotron Research Center, Life Science Collaborative Access Team, Northwestern University, Argonne, Illinois 60439.
authors.forename: Zdzislaw
authors.initials: Z
authors.lastname: Wawrzak
authors.affiliation: From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
authors.forename: Aidong
authors.initials: A
authors.lastname: Qi
authors.affiliation: Viamet Pharmaceuticals, Durham, North Carolina 27703, and.
authors.forename: William J
authors.initials: WJ
authors.lastname: Hoekstra
authors.affiliation: Viamet Pharmaceuticals, Durham, North Carolina 27703, and.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Schotzinger
authors.affiliation: From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
authors.forename: John D
authors.initials: JD
authors.lastname: York
authors.affiliation: From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
authors.forename: F Peter
authors.initials: FP
authors.lastname: Guengerich
authors.affiliation: From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, galina.i.lepesheva@vanderbilt.edu.|the Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232.
authors.forename: Galina I
authors.initials: GI
authors.lastname: Lepesheva
mesh_terms: D000818:Animals; D000935:Antifungal Agents / Q000737:chemistry*; D001393:Azoles / Q000737:chemistry*; D002176:Candida albicans / Q000201:enzymology*; D003460:Crystallization; D005656:Fungal Proteins / Q000737:chemistry*; D006418:Heme / Q000737:chemistry; D006801:Humans; D007700:Kinetics; D008024:Ligands; D008826:Microbial Sensitivity Tests; D011485:Protein Binding; D011487:Protein Conformation; D011522:Protons; D051381:Rats; D058886:Sterol 14-Demethylase / Q000737:chemistry*; D013261:Sterols / Q000096:biosynthesis*
chemical_list: D000935:Antifungal Agents; D001393:Azoles; D005656:Fungal Proteins; D008024:Ligands; D011522:Protons; D013261:Sterols; D006418:Heme; D058886:Sterol 14-Demethylase
keywords: Candida albicans; X-ray crystallography; antifungal drugs; cytochrome P450; enzyme inhibitor; enzyme kinetics; sterol 14 alpha-demethylase (CYP51); sterol biosynthesis