A Dynamic Core in Human NQO1 Controls the Functional and Stability Effects of Ligand Binding and Their Communication across the Enzyme Dimer
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Protein structural dynamicsLigand bindingProtein stabilityProtein degradationAllostery
Vankova, P., Salido, E., Timson, D. J., Man, P., & Pey, A. L. (2019). A Dynamic Core in Human NQO1 Controls the Functional and Stability Effects of Ligand Binding and Their Communication across the Enzyme Dimer. Biomolecules, 9(11), 728.
SponsorshipThis research was funded by the ERDF/Spanish Ministry of Science, Innovation and Universities—State Research Agency (Grant RTI2018-096246-B-I00, to A.L.P.), the Spanish Ministry of Economy and Competitiveness (Grant SAF2015-69796, to E.S.) and Junta de Andalucía (Grant P11-CTS-07187, to ALP). Access to an EU_FT–ICR_MS network installation was funded by the EU Horizon 2020 grant 731077. Additional support from Aula FUNCANIS-UGR, EU and MEYS CZ funds CZ.1.05/1.1.00/02.0109, LQ1604 and LM2015043 is gratefully acknowledged.
Human NAD(P)H:quinone oxidoreductase 1 (NQO1) is a multi-functional protein whose alteration is associated with cancer, Parkinson’s and Alzheimer´s diseases. NQO1 displays a remarkable functional chemistry, capable of binding different functional ligands that modulate its activity, stability and interaction with proteins and nucleic acids. Our understanding of this functional chemistry is limited by the difficulty of obtaining structural and dynamic information on many of these states. Herein, we have used hydrogen/deuterium exchange monitored by mass spectrometry (HDXMS) to investigate the structural dynamics of NQO1 in three ligation states: without ligands (NQO1apo), with FAD (NQO1holo) and with FAD and the inhibitor dicoumarol (NQO1dic). We show that NQO1apo has a minimally stable folded core holding the protein dimer, with FAD and dicoumarol binding sites populating binding non-competent conformations. Binding of FAD significantly decreases protein dynamics and stabilizes the FAD and dicoumarol binding sites as well as the monomer:monomer interface. Dicoumarol binding further stabilizes all three functional sites, a result not previously anticipated by available crystallographic models. Our work provides an experimental perspective into the communication of stability effects through the NQO1 dimer, which is valuable for understanding at the molecular level the effects of disease-associated variants, post-translational modifications and ligand binding cooperativity in NQO1.