2C76

Functional Role of the Aromatic Cage in Human Monoamine Oxidase B: Structures and Catalytic Properties of Tyr435 Mutant Proteins

Summary for 2C76

• Entry DOI: 10.2210/pdb2c76/pdb
• Related: 1GOS 1H8R 1OJ9 1OJA 1OJB 1OJC 1OJD 1S2Q 1S2Y 1S3B 1S3E 2BK3 2BK4 2BK5 2BYB 2C64 2C65 2C66 2C67 2C70 2C72 2C73 2C75
• Descriptor: AMINE OXIDASE (FLAVIN-CONTAINING) B, FLAVIN-ADENINE DINUCLEOTIDE, N-PROPARGYL-1(S)-AMINOINDAN, ... (4 entities in total)
• Functional Keywords: oxidoreductase, enantioselectivity, fad, flavin, flavoprotein, human monoamine oxidase, inhibitor binding, mitochondrion, rasagiline, transmembrane, parkinson, acetylation
• Biological source: HOMO SAPIENS (HUMAN)
• Cellular location: Mitochondrion outer membrane; Single-pass type IV membrane protein; Cytoplasmic side: P27338
• Total number of polymer chains: 2
• Total formula weight: 119635.12

Authors

Li, M.,Binda, C.,Mattevi, A.,Edmondson, D.E. (deposition date: 2005-11-17, release date: 2006-04-19, Last modification date: 2024-10-23)

Primary citation

Li, M.,Binda, C.,Mattevi, A.,Edmondson, D.E.
Functional Role of the Aromatic Cage in Human Monoamine Oxidase B: Structures and Catalytic Properties of Tyr435 Mutant Proteins
Biochemistry, 45:4775-, 2006

PubMed Abstract: Current structural results of several flavin-dependent amine oxidizing enzymes including human monoamine oxidases A and B (MAO A and MAO B) show aromatic amino acid residues oriented approximately perpendicular to the flavin ring, suggesting a functional role in catalysis. In the case of human MAO B, two tyrosyl residues (Y398 and Y435) are found in the substrate binding site on the re face of the covalent flavin ring [Binda et al. (2002) J. Biol. Chem. 277, 23973-23976]. To probe the functional significance of this structure, Tyr435 in MAO B was mutated with the amino acids Phe, His, Leu, or Trp, the mutant proteins expressed in Pichia pastoris, and purified to homogeneity. Each mutant protein contains covalent FAD and exhibits a high level of catalytic functionality. No major alterations in active site structures are detected on comparison of their respective crystal structures with that of WT enzyme. The relative k(cat)/K(m) values for each mutant enzyme show Y435 > Y435F = Y435L = Y435H > Y435W. A similar behavior is also observed with the membrane-bound forms of MAO A and MAO B (MAO A Y444 mutant enzymes are found to be unstable on membrane extraction). p-Nitrobenzylamine is found to be a poor substrate while p-nitrophenethylamine is found to be a good substrate for all WT and mutant forms of MAO B. Analysis of these kinetic and structural data suggests the function of the "aromatic cage" in MAO to include a steric role in substrate binding and access to the flavin coenzyme and to increase the nucleophilicity of the substrate amine moiety. These results are consistent with a proposed polar nucleophilic mechanism for catalytic amine oxidation.

PubMed: 16605246
DOI: 10.1021/BI051847G

Experimental method

X-RAY DIFFRACTION (1.7 Å)