Researchers from the Structural and Molecular Biology research group at UCIBIO-FCT NOVA, have just published a new study describing a new crystal structure of the complex human aldehyde oxidase and its most potent inhibitor raloxifene, widely used in biochemical assays. This structure elucidates the unusual substrate-dependent mechanism of inhibition with potential impact on drug–drug interactions. The research work was led by Maria João Romão, leader of the XTAL - Macromolecular Crystallography Lab, and Filipa Marcelo, researcher at (Bio)molecular Structure and Interactions by NMR Lab, and the results were published in the Journal of Medicinal Chemistry.
Human aldehyde oxidase (hAOX1) is mainly present in the liver and has an emerging role in drug metabolism, since it accepts a wide range of molecules as substrates and inhibitors. The research team involved in this work aimed to screen inhibitors and substrates of the promiscuous human aldehyde oxidase to predict its metabolism and find more about binding modes and inhibition mechanisms.
The first author of the paper, Cristiano Mota, researcher at the XTAL - Macromolecular Crystallography Lab, explains that “we used 3 different approaches (X-ray crystallography, NMR spectroscopy and kinetic assays) and combined the results to infer about the inhibition mechanisms and binding sites. We were able to determine the binding sites of raloxifene and thioridazine and conclude about their inhibition mechanisms”. Ana Diniz, PhD student at the (Bio)molecular Structure and Interactions by NMR Lab, adds that “regarding the mixed-type inhibitor, benzamidine, the competitive STD-NMR assays allowed to speculate about the binding sites.”
This study can be considered as a proof-of-concept for an efficient experimental screening of prospective substrates and inhibitors of human aldehyde oxidase, relevant in drug discovery.
Interrogating the Inhibition Mechanisms of Human Aldehyde Oxidase by X-ray Crystallography and NMR Spectroscopy: The Raloxifene Case, Cristiano Mota, Ana Diniz, Catarina Coelho, Teresa Santos-Silva, Mariam Esmaeeli, Silke Leimkühler, Eurico J. Cabrita, Filipa Marcelo, and Maria João Romão, Journal of Medicinal Chemistry