The first mammalian aldehyde oxidase crystal structure: Insights into substrate specificity

This work was supported by the Portuguese Science and Technology Foundation (FCT-MCTES) through Project PTDC/BIA-PRO/118377/2010 and Grant SFRH/BD/37948/2007(to C. C.) and by the Cluster of Excellence "Unifying Concepts in Catalysis" (to S. L. and M. M.) coordinated by the Technische Universitat Berlin and funded by the Deutsche Forschungsgemeinschaft. The exchange of researchers among laboratories was funded by the DAAD-GRICES program (to M. J. R. and S. L.). The work was also supported by grants from the Associazione Italiana per la Ricerca controil Cancro(AIRC), the Fondazione Italo Monzino, and the Negri-Weizmann Foundation (to E. G.).Aldehyde oxidases (AOXs) are homodimeric proteins belonging to the xanthine oxidase family of molybdenum-containing enzymes. Each 150-kDa monomer contains a FAD redox cofactor, two spectroscopically distinct [2Fe-2S] clusters, and a molybdenum cofactor located within the protein active site. AOXs are characterized by broad range substrate specificity, oxidizing different aldehydes and aromatic N-heterocycles. Despite increasing recognition of its role in the metabolism of drugs and xenobiotics, the physiological function of the protein is still largely unknown. We have crystallized and solved the crystal structure of mouse liver aldehyde oxidase 3 to 2.9A? . This is the first mammalian AOX whose structure has been solved. The structureprovidesimportantinsightsintotheproteinactivecenter and further evidence on the catalytic differences characterizing AOXand xanthine oxidoreductase. The mouse liver aldehyde oxidase 3 three-dimensional structure combined with kinetic, mutagenesis data, molecular docking, and molecular dynamics studies make a decisive contribution to understand the molecular basis of its rather broad substrate specificity.publishersversionpublishe