Interaction of Mycobacterium tuberculosis CYP130 with heterocyclic arylamines.
The Mycobacterium tuberculosis P450 enzymes are of interest for their pharmacological development potential, as evidenced by their susceptibility to inhibition by antifungal azole drugs that normally target sterol 14alpha-demethylase (CYP51). Although antifungal azoles show promise, direct screening of compounds against M. tuberculosis P450 enzymes may identify novel, more potent, and selective inhibitory scaffolds. Here we report that CYP130 from M. tuberculosis has a natural propensity to bind primary arylamines with particular chemical architectures. These compounds were identified via a high throughput screen of CYP130 with a library of synthetic organic molecules. As revealed by subsequent x-ray structure analysis, selected compounds bind in the active site by Fe-coordination and hydrogen bonding of the arylamine group to the carbonyl oxygen of Gly(243). As evidenced by the binding of structural analogs, the primary arylamine group is indispensable, but synergism due to hydrophobic contacts between the rest of the molecule and protein amino acid residues is responsible for a binding affinity comparable with that of the antifungal azole drugs. The topology of the CYP130 active site favors angular coordination of the arylamine group over the orthogonal coordination of azoles. Upon substitution of Gly(243) by an alanine, the binding mode of azoles and some arylamines reverted from type II to type I because of hydrophobic and steric interactions with the alanine side chain. We suggest a role for the conserved Ala(Gly)(243)-Gly(244) motif in the I-helix in modulating both the binding affinity of the axial water ligand and the ligand selectivity of cytochrome P450 enzymes.
Podust
Larissa M
LM
Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158, USA.
Ouellet
Hugues
H
von Kries
Jens P
JP
de Montellano
Paul R Ortiz
PR
D000588:Amines / Q000737:chemistry*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism; D002384:Catalysis; D020134:Catalytic Domain; D018360:Crystallography, X-Ray / Q000379:methods; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D015723:Gene Library; D008024:Ligands; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000378:metabolism*; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D013053:Spectrophotometry / Q000379:methods
D000588:Amines; D001426:Bacterial Proteins; C527931:CYP130 protein, M tuberculosis; D008024:Ligands; D003577:Cytochrome P-450 Enzyme System; C501935:cytochrome P-450 CYP51, Mycobacterium tuberculosis