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Exposing the Interplay Between Enzyme Turnover, Protein Dynamics and the Membrane Environment in Monoamine Oxidase B

Research output: Contribution to journalArticle

Original languageEnglish
Pages (from-to)2362-2372
Number of pages11
JournalBiochemistry
Volume58
Issue number18
Early online date9 Apr 2019
DOIs
DateAccepted/In press - 9 Apr 2019
DateE-pub ahead of print - 9 Apr 2019
DatePublished (current) - 7 May 2019

Abstract

There is an increasing realization that structure-based drug design may show improved success by understanding the ensemble of conformations accessible to an enzyme and how the environment affects this ensemble. Human monoamine oxidase B (MAO-B) catalyzes the oxidation of amines and is inhibited for the treatment of both Parkinson's disease and depression. Despite its clinical importance, its catalytic mechanism remains unclear, and routes to drugging this target would be valuable. Evidence of a radical in either the transition state or the resting state of MAO-B is present throughout the literature and is suggested to be a flavin semiquinone, a tyrosyl radical, or both. Here we see evidence of a resting-state flavin semiquinone, via absorption redox studies and electron paramagnetic resonance, suggesting that the anionic semiquinone is biologically relevant. On the basis of enzyme kinetic studies, enzyme variants, and molecular dynamics simulations, we find evidence for the importance of the membrane environment in mediating the activity of MAO-B and that this mediation is related to the protein dynamics of MAO-B. Further, our MD simulations identify a hitherto undescribed entrance for substrate binding, membrane modulated substrate access, and indications for half-site reactivity: only one active site is accessible to binding at a time. Our study combines both experimental and computational evidence to illustrate the subtle interplay between enzyme activity and protein dynamics and the immediate membrane environment. Understanding key biomedical enzymes to this level of detail will be crucial to inform strategies (and binding sites) for rational drug design for these targets. ©

    Research areas

  • EPR, Molecular Dynamics, Monoamine Oxidase B, semiquinone, enzyme, flavin, membrane

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  • Full-text PDF (accepted author manuscript)

    Rights statement: This is the author accepted manuscript (AAM). The final published version (version of record) is available online via ACS at https://pubs.acs.org/doi/10.1021/acs.biochem.9b00213 . Please refer to any applicable terms of use of the publisher.

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