rasagiline-inhibited human monoamine oxidase B in complex with 2-(2- benzofuranyl)-2-imidazoline
[AOFB_HUMAN] Catalyzes the oxidative deamination of biogenic and xenobiotic amines and has important functions in the metabolism of neuroactive and vasoactive amines in the central nervous system and peripheral tissues. MAOB preferentially degrades benzylamine and phenylethylamine.
Publication Abstract from PubMed
Crystallographic and biochemical studies have been employed to identify the binding site and mechanism for potentiation of imidazoline-binding in human monoamine oxidase B (MAO B). 2-(2-Benzofuranyl)-2-imidazoline (2-BFI) inhibits recombinant human MAO B with a Ki of 8.3+/-0.6 muM whereas tranylcypromine-inhibited MAO B binds 2-BFI with a Kd of 9+/-2 nM, representing an increase in binding energy Delta(DeltaG) of -3.9 kcal/mol. Crystal structures show the imidazoline ligand bound in a site that is distinct from the substrate-binding cavity. Contributions to account for the increase in binding affinity upon tranylcypromine inhibition include a conformational change in the side chain of Gln206 and a "closed conformation" of the side chain of Ile199, forming a hydrophobic "sandwich" with the side chain of Ile316 on each face of the benzofuran ring of 2-BFI. Data with the Ile199Ala mutant of human MAO B and failure to observe a similar binding potentiation with rat MAO B, where Ile316 is replaced with a Val residue, support an allosteric mechanism where the increased binding affinity of 2-BFI results from a cooperative increase in H-bond strength through formation of a more hydrophobic milieu. These insights should prove valuable in the design of high affinity and specific reversible MAO B inhibitors.
Potentiation of ligand binding through cooperative effects in monoamine oxidase B.,Bonivento D, Milczek EM, McDonald GR, Binda C, Holt A, Edmondson DE, Mattevi A J Biol Chem. 2010 Sep 20. PMID:20855894
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.