Once the molecule file is fully loaded, the image at right will become live. At that time the "activate 3-D" icon will disappear.

Copper Oxidases/Oxygenases

This page shows some interactive JSmol views of several type 2 copper oxidase enzymes


The first figure [PHM] shows the structure of the copper monooxygenase enzyme peptidylglycine α-hydroxylating monooxygenase (PHM), its function is to carry out regio- and stereospecific hydroxylation of secondary C-H bonds. Note that, although the structure appears to have two similar domains, it is not a dimer.

The protein contains two copper ions but they are separated by about 10 Å (check for yourself) - so they are not coupled together. One site (that shown on the right with 3 His ligands) is probably an electron transfer site; the other is the active site for the catalysis.

[PHM2] shows the active site with dioxygen bound to the active site (as Cu(II)—O2·–). This form is produced by reaction of O2 The active site also contains a small peptide in the active site - this is the substrate that will be hydroxylated (in the case of this particular substrate, N-acetyl-3,5-diiodotyrosyl-D-threonine, the reaction is slow).
Measure the bonds in the Cu(II)—O2·– assembly. Are they consistent with this description?


Quercetinase is a type 2 copper dioxygenase - the only copper dioxygenase known and a very rare example of a copper metalloprotein with a carboxylate ligand. The figure shows the exzyme-substrate complex with quercetin bound to the copper center.

Galactose oxidase and the class of amine oxidases catalyse two-electron oxidation. Since only one electron can come from the copper another redox-active cofactor is needed.

Both enzymes contain modified groups synthesised by the enzyme itself after its initial assembly. In amine oxidases a tyrosine residue is oxidised to 2,4,5-trihydroxyl-phenylalanine quinone (TPQ) ; in galactose oxidase a tyrosine is crosslinked to a cysteine. Both modified groups sit in the active site but not bound to the copper ion.

Return to the index page.

Written by V. McKee based on template by A. Herráez as modified by J. Gutow.
updated November 2019.
This will be the viewer still of jmol image
Rattus norvegicus PHM from: "Dioxygen Binds End-On to Mononuclear Copper in a Precatalytic Enzyme Complex." S. T. Prigge, B. A. Eipper, R. E. Mains and L. M. Amzel. Science, 2004, 304, 864-867. (PDB code 1SDW).
Quercetinase data from: "Anaerobic Enzyme.Substrate Structures Provide Insight Into the Reaction Mechanism of the Copper- Dependent Quercetin 2,3-Dioxygenase". Steiner, R.A., Kalk, K.H., Dijkstra, B.W. (2002) Proc.Natl.Acad.Sci. USA 99: 16625. (PDB code 1H1I)
Galactose oxidase data from: "Novel thioether bond revealed by a 1.7 A crystal structure of galactose oxidase". Ito, N., Phillips, S.E., Stevens, C., Ogel, Z.B., McPherson, M.J., Keen, J.N., Yadav, K.D., Knowles, P.F. (1991) Nature 350: 87-90. (PDB code 1GOG).
Amine oxidase data from: "X-ray snapshots of quinone cofactor biogenesis in bacterial copper amine oxidase" Kim, M., Okajima, T., Kishishita, S., Yoshimura, M., Kawamori, A., Tanizawa, K., Yamaguchi, H. (2002) Nat.Struct.Mol.Biol. 9: 591-596 (PDB code 1IVX)

Return to the index page.