2cib

File:2cib.gif

spinqualitylabelsall models 2cib, resolution 1.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

HIGH THROUGHPUT SCREENING AND X-RAY CRYSTALLOGRAPHY ASSISTED EVALUATION OF SMALL MOLECULE SCAFFOLDS FOR CYP51 INHIBITORS

OverviewOverview

Sterol 14alpha-demethylase (CYP51), a major checkpoint in membrane sterol, biosynthesis, is a key target for fungal antibiotic therapy. We sought, small organic molecules for lead candidate CYP51 inhibitors. The changes, in CYP51 spectral properties following ligand binding make it a convenient, target for high throughput screening (HTS) technologies. These changes are, characteristic of either substrate binding (type I) or inhibitor binding, (type II) in the active site. We screened a library of 20,000 organic, molecules against Mycobacterium tuberculosis CYP51 (MtCYP51) and examined, the top type I and type II binding hits for their inhibitory effects, against M. tuberculosis in broth culture and spectrally for their ability, to discriminate between MtCYP51 and two reference M. tuberculosis CYP, proteins, CYP130 and CYP125. We determined the binding mode for one of the, top type II hits, alpha-ethyl-N-4-pyridinyl-benzeneacetamide (EPBA), by, solving the x-ray structure of the MtCYP51/EPBA complex to a resolution of, 1.53 A. EPBA binds coordinately to the heme iron in the MtCYP51 active, site through a lone pair of nitrogen electrons and also through hydrogen, bonds with residues H259 and Y76, which are invariant in the CYP51 family, and hydrophobic interactions in a phylum- and/or substrate-specific cavity, of CYP51. We also identified a second compound with structural and binding, properties similar to EPBA, (2-[(2,1,3-benzothiadiazol-4-sulfonamide]-2-phenyl-N-pyridin-4-acetamide, (BSPPA). The congruence between the geometries of EPBA and BSPPA and the, CYP51 binding site singles them out as lead candidate CYP51 inhibitors, with optimization potential for efficient discrimination between host and, pathogen enzymes.

About this StructureAbout this Structure

2CIB is a Single protein structure of sequence from Mycobacterium tuberculosis with HEM and CM6 as ligands. Active as Sterol 14-demethylase, with EC number 1.14.13.70 Structure known Active Sites: AC1 and AC2. Full crystallographic information is available from OCA.

ReferenceReference

Small Molecule Scaffolds for CYP51 Inhibitors Identified by High Throughput Screening and Defined by X-Ray Crystallography., Podust LM, von Kries JP, Eddine AN, Kim Y, Yermalitskaya LV, Kuehne R, Ouellet H, Warrier T, Altekoster M, Lee JS, Rademann J, Oschkinat H, Kaufmann SH, Waterman MR, Antimicrob Agents Chemother. 2007 Sep 10;. PMID:17846131

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