SSF54416

Amine oxidase N-terminal region

SUPERFAMILY entry
Member databaseSUPERFAMILY
SUPERFAMILY typehomologous superfamily

Description
Imported from IPR016182

This entry represents the N-terminal region of copper amine oxidases, and has a core structure consisting of α-β(4), where the helix packs against the coiled antiparallel β-sheet
[1]
. A domain with a similar structural fold can be found as the first and second domains in lysyl oxidase PplO
[2]
.

Amine oxidases (AO) are enzymes that catalyse the oxidation of a wide range of biogenic amines including many neurotransmitters, histamine and xenobiotic amines. There are two classes of amine oxidases: flavin-containing (
1.4.3.4
) and copper-containing (
1.4.3.6
). Copper-containing AO act as a disulphide-linked homodimer. They catalyse the oxidation of primary amines to aldehydes, with the subsequent release of ammonia and hydrogen peroxide, which requires one copper ion per subunit and topaquinone as cofactor
[1]
: RCH2NH2 + H2O + O2 = RCHO + NH3 + H2O2

Copper-containing amine oxidases are found in bacteria, fungi, plants and animals. In prokaryotes, the enzyme enables various amine substrates to be used as sources of carbon and nitrogen
[3, 4]
. In eukaryotes they have a broader range of functions, including cell differentiation and growth, wound healing, detoxification and cell signalling
[5]
.

The copper amine oxidases occur as mushroom-shaped homodimers of 70-95kDa, 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 β sandwich of 18 strands in two sheets. The active site is buried and requires a conformational change to allow the substrate access. The two N-terminal domains share a common structural fold, its core consisting of a five-stranded antiparallel β-sheet twisted around an α-helix. The D1 domains from the two subunits comprise the stalk, of the mushroom-shaped dimer, and interact with each other but do not pack tightly against each other
[1, 6]
.

References
Imported from IPR016182

1.Crystal structure of a quinoenzyme: copper amine oxidase of Escherichia coli at 2 A resolution. Parsons MR, Convery MA, Wilmot CM, Yadav KD, Blakeley V, Corner AS, Phillips SE, McPherson MJ, Knowles PF. Structure 3, 1171-84, (1995). View articlePMID: 8591028

2.The crystal structure of Pichia pastoris lysyl oxidase. Duff AP, Cohen AE, Ellis PJ, Kuchar JA, Langley DB, Shepard EM, Dooley DM, Freeman HC, Guss JM. Biochemistry 42, 15148-57, (2003). View articlePMID: 14690425

3.Catalytic mechanism of the quinoenzyme amine oxidase from Escherichia coli: exploring the reductive half-reaction. Wilmot CM, Murray JM, Alton G, Parsons MR, Convery MA, Blakeley V, Corner AS, Palcic MM, Knowles PF, McPherson MJ, Phillips SE. Biochemistry 36, 1608-20, (1997). View articlePMID: 9048544

4.Crystal structures of the copper-containing amine oxidase from Arthrobacter globiformis in the holo and apo forms: implications for the biogenesis of topaquinone. Wilce MC, Dooley DM, Freeman HC, Guss JM, Matsunami H, McIntire WS, Ruggiero CE, Tanizawa K, Yamaguchi H. Biochemistry 36, 16116-33, (1997). View articlePMID: 9405045

5.Crystal structure of a eukaryotic (pea seedling) copper-containing amine oxidase at 2.2 A resolution. Kumar V, Dooley DM, Freeman HC, Guss JM, Harvey I, McGuirl MA, Wilce MC, Zubak VM. Structure 4, 943-55, (1996). View articlePMID: 8805580

6.Visualization of dioxygen bound to copper during enzyme catalysis. Wilmot CM, Hajdu J, McPherson MJ, Knowles PF, Phillips SE. Science 286, 1724-8, (1999). View articlePMID: 10576737

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