PDBsum entry 2c75

Oxidoreductase

PDB id: 2c75

Contents

Protein chain

499 a.a. *

Ligands

FAD-RSA ×2

Waters ×881

* Residue conservation analysis

PDB id:

2c75

Name:

Oxidoreductase

Title:

Functional role of the aromatic cage in human monoamine oxidase b: structures and catalytic properties of tyr435 mutant proteins

Structure:

Amine oxidase (flavin-containing) b. Chain: a, b. Synonym: monoamine oxidase b, mao-b. Engineered: yes. Mutation: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: pichia pastoris. Expression_system_taxid: 4922

Biol. unit:

Dimer (from PDB file)

Resolution:

1.70Å R-factor: 0.189 R-free: 0.209

Authors:

M.Li,C.Binda,A.Mattevi,D.E.Edmondson

Key ref:

M.Li et al. (2006). Functional role of the "aromatic cage" in human monoamine oxidase B: structures and catalytic properties of Tyr435 mutant proteins. Biochemistry, 45, 4775-4784. PubMed id: 16605246 DOI: 10.1021/bi051847g

Date:

17-Nov-05 Release date: 19-Apr-06

Protein chains

P27338  (AOFB_HUMAN) -  Amine oxidase [flavin-containing] B from Homo sapiens

Seq: 520 a.a.

Struc: 499 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class 2: E.C.1.4.3.21 - primary-amine oxidase.
• Reaction: a primary methyl amine + O2 + H2O = an aldehyde + H2O2 + NH4⁺
• Enzyme class 3: E.C.1.4.3.4 - monoamine oxidase.
• Reaction: a secondary aliphatic amine + O2 + H2O = a primary amine + an aldehyde + H2O2
• Cofactor: FAD

FAD (Bound ligand (Het Group name = FAD) corresponds exactly)

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

DOI no: 10.1021/bi051847g

Biochemistry 45:4775-4784 (2006)

PubMed id: 16605246

Functional role of the "aromatic cage" in human monoamine oxidase B: structures and catalytic properties of Tyr435 mutant proteins.

M.Li, C.Binda, A.Mattevi, D.E.Edmondson.

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.