Structure
The copper amine oxidase 3-dimensional structure was determined through X-ray crystallography. The copper amine oxidases occur as mushroom-shaped homodimers of 70-95 kDa, each monomer containing a copper ion and a covalently bound redox cofactor, topaquinone (TPQ). TPQ is formed by post-translational modification of a conserved tyrosine residue. The copper ion is coordinated with three histidine residues and two water molecules in a distorted square pyramidal geometry, and has a dual function in catalysis and TPQ biogenesis. The catalytic domain is the largest of the 3-4 domains found in copper amine oxidases, and consists of a beta sandwich of 18 strands in two sheets. The active site is buried and requires a conformational change to allow the substrate access.
The N2 and N3 N-terminal domains share a common structural fold, its core consisting of alpha-beta(4), where the helix is packed against the coiled anti-parallel beta-sheets. An additional domain is found at the N-terminal of some copper amine oxidases, as well as in related proteins such as cell wall hydrolase and N-acetylmuramoyl-L-alanine amidase. This domain consists of a five-stranded antiparallel beta-sheet twisted around an alpha helix.
Read more about this topic: Amine Oxidase (copper-containing)
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