This application seeks continued funding to investigate the structure and function of human Monoamine Oxidases A and B (MAO A and MAO B) which are located in the outer mitochondrial membrane and catalyze the oxidation of amine neuro-transmitters and xenobiotic amines. The elucidation of the 3- dimensional structure of each enzyme during the past period of support has resulted in new questions which will require an integrated approach of investigation of their membrane structures and functions which are addressed by five specific aims. Extended structural studies will seek a higher resolution structure of MAO A complexed with clinically used inhibitors as well as the structures of both enzymes in model membrane Nanodiscs to test current models of MAO-membrane interactions. The structural/functional role of a MAO A Glu151Lys mutation which is a selection mutation for the human will be investigated to understand the functional role of this mutation and its proposed role in altering the oligomeric state of human MAO A. The topological localization of both MAO A and MAO B in the outer mitochondrial membrane will be determined in human and other mammalian mitochondria with regard to correlations of inhibitor function and the degradative effect of hydrogen peroxide produced on MAO catalysis. Mechanistic studies will investigate the role of a tyrosine """"""""aromatic cage"""""""" situated in the active site in front of the covalent flavin and the proposed influence of their coupled dipoles in amine activation. From predictions of model calculations, the role of Lys296 in the reaction of substrate-reduced flavin with oxygen in catalytic turnover will be determined using mutagenesis approaches. Fluorescence and spin label EPR studies will be used as probes of the oligomeric states and structures of the membrane-bound forms of each enzyme and the results compared with available structural data. Mechanistic studies will be extended to test possible models for the mechanism- based inhibition of MAO A and MAO B by the acetylenic and cyclopropyl amine irreversible inhibitors. The results of this investigation should provide new insights into the molecular basis for the development of new and highly specific MAO A and MAO B inhibitors that would have clinical benefit. The MAO B inhibitors would function as neuroprotective agents for the prevention of and treatment of age-related neurological disorders. The MAO A inhibitors could have clinical benefit as new types of anti-depressants. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM029433-25
Application #
7394989
Study Section
Biochemistry and Biophysics of Membranes Study Section (BBM)
Program Officer
Anderson, Vernon
Project Start
1982-07-01
Project End
2010-03-31
Budget Start
2008-04-01
Budget End
2009-03-31
Support Year
25
Fiscal Year
2008
Total Cost
$417,360
Indirect Cost
Name
Emory University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
066469933
City
Atlanta
State
GA
Country
United States
Zip Code
30322
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Martinoli, Christian; Dudek, Hanna M; Orru, Roberto et al. (2013) Beyond the Protein Matrix: Probing Cofactor Variants in a Baeyer-Villiger Oxygenation Reaction. ACS Catal 3:3058-3062
Orru, R; Aldeco, M; Edmondson, D E (2013) Do MAO A and MAO B utilize the same mechanism for the C-H bond cleavage step in catalysis? Evidence suggesting differing mechanisms. J Neural Transm (Vienna) 120:847-51
Binda, Claudia; Aldeco, Milagros; Mattevi, Andrea et al. (2011) Interactions of monoamine oxidases with the antiepileptic drug zonisamide: specificity of inhibition and structure of the human monoamine oxidase B complex. J Med Chem 54:909-12
Wang, Jin; Edmondson, Dale E (2011) ²H kinetic isotope effects and pH dependence of catalysis as mechanistic probes of rat monoamine oxidase A: comparisons with the human enzyme. Biochemistry 50:7710-7
Aldeco, Milagros; Arslan, Betul Kacar; Edmondson, Dale E (2011) Catalytic and inhibitor binding properties of zebrafish monoamine oxidase (zMAO): comparisons with human MAO A and MAO B. Comp Biochem Physiol B Biochem Mol Biol 159:78-83
Milczek, Erika M; Binda, Claudia; Rovida, Stefano et al. (2011) The 'gating' residues Ile199 and Tyr326 in human monoamine oxidase B function in substrate and inhibitor recognition. FEBS J 278:4860-9
Wang, Jin; Edmondson, Dale E (2011) Topological probes of monoamine oxidases A and B in rat liver mitochondria: inhibition by TEMPO-substituted pargyline analogues and inactivation by proteolysis. Biochemistry 50:2499-505
Binda, Claudia; Mattevi, Andrea; Edmondson, Dale E (2011) Structural properties of human monoamine oxidases A and B. Int Rev Neurobiol 100:1-11
Binda, Claudia; Aldeco, Milagros; Geldenhuys, Werner J et al. (2011) Molecular Insights into Human Monoamine Oxidase B Inhibition by the Glitazone Anti-Diabetes Drugs. ACS Med Chem Lett 3:39-42

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