6cr2
From Proteopedia
Crystal structure of sterol 14-alpha demethylase (CYP51B) from Aspergillus fumigatus in complex with the VNI derivative N-(1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethyl)-4-(5-(2-fluoro-4-(2,2,2-trifluoroethoxy)phenyl)-1,3,4-oxadiazol-2-yl)benzamide
Structural highlights
FunctionCP51B_ASPFU Sterol 14-alpha demethylase; part of the third module of ergosterol biosynthesis pathway that includes the late steps of the pathway (PubMed:18191972, PubMed:26459890, PubMed:29439966, PubMed:9184358). Demethylates eburicol to yield 4,4,24-trimethyl ergosta-8,14,24(28)-trienol (PubMed:18191972, PubMed:26459890, PubMed:29439966, PubMed:9184358). The third module or late pathway involves the ergosterol synthesis itself through consecutive reactions that mainly occur in the endoplasmic reticulum (ER) membrane. Firstly, the squalene synthase erg9 catalyzes the condensation of 2 farnesyl pyrophosphate moieties to form squalene, which is the precursor of all steroids. Squalene synthase is crucial for balancing the incorporation of farnesyl diphosphate (FPP) into sterol and nonsterol isoprene synthesis. Secondly, squalene is converted into lanosterol by the consecutive action of the squalene epoxidase erg1 and the lanosterol synthase erg7. Then, the delta(24)-sterol C-methyltransferase erg6 methylates lanosterol at C-24 to produce eburicol. Eburicol is the substrate of the sterol 14-alpha demethylase encoded by cyp51A and cyp51B, to yield 4,4,24-trimethyl ergosta-8,14,24(28)-trienol. The C-14 reductase erg24 then reduces the C14=C15 double bond which leads to 4,4-dimethylfecosterol. A sequence of further demethylations at C-4, involving the C-4 demethylation complex containing the C-4 methylsterol oxidases erg25A or erg25B, the sterol-4-alpha-carboxylate 3-dehydrogenase erg26 and the 3-keto-steroid reductase erg27, leads to the production of fecosterol via 4-methylfecosterol. The C-8 sterol isomerase erg2 then catalyzes the reaction which results in unsaturation at C-7 in the B ring of sterols and thus converts fecosterol to episterol. The sterol-C5-desaturase erg3B then catalyzes the introduction of a C-5 double bond in the B ring to produce 5-dehydroepisterol. The 2 other sterol-C5-desaturases, erg3A and erg3C, seem to be less important in ergosterol biosynthesis. The C-22 sterol desaturase erg5 further converts 5-dehydroepisterol into ergosta-5,7,22,24(28)-tetraen-3beta-ol by forming the C-22(23) double bond in the sterol side chain. Finally, ergosta-5,7,22,24(28)-tetraen-3beta-ol is substrate of the C-24(28) sterol reductases erg4A and erg4B to produce ergosterol. Possible alternative sterol biosynthetic pathways might exist from fecosterol to ergosterol, depending on the activities of the erg3 isoforms (PubMed:16110826, PubMed:18191972) (Probable).[1] [2] [3] [4] [5] [6] As a target of azole drugs, plays a crucial role in azole susceptibility.[7] [8] [9] [10] Publication Abstract from PubMedBecause of the increase in the number of immunocompromised patients, the incidence of invasive fungal infections is growing, but the treatment efficiency remains unacceptably low. The most potent clinical systemic antifungals (azoles) are the derivatives of two scaffolds: ketoconazole and fluconazole. Being the safest antifungal drugs, they still have shortcomings, mainly because of pharmacokinetics and resistance. Here, we report the successful use of the target fungal enzyme, sterol 14alpha-demethylase (CYP51), for structure-based design of novel antifungal drug candidates by minor modifications of VNI [( R)- N-(1-(2,4-dichlorophenyl)-2-(1 H-imidazol-1-yl)ethyl)-4-(5-phenyl-1,3,4-oxadiazol-2-yl)benzamide)], an inhibitor of protozoan CYP51 that cures Chagas disease. The synthesis of fungi-oriented VNI derivatives, analysis of their potencies to inhibit CYP51s from two major fungal pathogens ( Aspergillus fumigatus and Candida albicans), microsomal stability, effects in fungal cells, and structural characterization of A. fumigatus CYP51 in complexes with the most potent compound are described, offering a new antifungal drug scaffold and outlining directions for its further optimization. Sterol 14alpha-Demethylase Structure-Based Design of VNI (( R)- N-(1-(2,4-Dichlorophenyl)-2-(1 H-imidazol-1-yl)ethyl)-4-(5-phenyl-1,3,4-oxadiazol-2-yl)benzamide)) Derivatives To Target Fungal Infections: Synthesis, Biological Evaluation, and Crystallographic Analysis.,Friggeri L, Hargrove TY, Wawrzak Z, Blobaum AL, Rachakonda G, Lindsley CW, Villalta F, Nes WD, Botta M, Guengerich FP, Lepesheva GI J Med Chem. 2018 Jun 25. doi: 10.1021/acs.jmedchem.8b00641. PMID:29894182[11] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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