Evidence of a self-catalytic mechanism of 2,4,5-trihydroxyphenylalanine quinone biogenesis in yeast copper amine oxidase.
Copper amine oxidases are representative of a new class of redox enzymes that contain a peptide-bound quinone cofactor, generated by posttranslational modification of amino acid side chain(s). We have investigated the mechanism for the biogenesis of 2,4,5-trihydroxyphenylalanine quinone (TPQ) in amine oxidase with two site-specific mutants of the yeast methylamine oxidase. Our results show that the capacity for TPQ formation in vivo is abolished when a putative ligand to copper, His-456, is changed to Asp; this H456D mutant binds copper at a low level (approximately 4.1%), relative to the wild-type protein. In contrast, altering the active site consensus sequence that contains the precursor tyrosine does not affect TPQ production. The data implicate a self-catalysis mechanism for TPQ biogenesis, in which the protein-bound copper plays a key role. We propose that the minimal information required for TPQ biogenesis lies in a structural motif consisting of the copper site and the precursor tyrosine.
Cai
D
D
Department of Chemistry, University of California, Berkeley 94720-1460.
Klinman
J P
JP
D006631:Amine Oxidase (Copper-Containing) / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002384:Catalysis; D003067:Coenzymes / Q000096:biosynthesis*; D016384:Consensus Sequence; D003300:Copper / Q000378:metabolism; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives* / Q000096:biosynthesis; D007700:Kinetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
C086758:2,4,5-trihydroxyphenylalanine quinone; D003067:Coenzymes; D009838:Oligodeoxyribonucleotides; D004295:Dihydroxyphenylalanine; D003300:Copper; D006631:Amine Oxidase (Copper-Containing)