This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
Journal:JBIC:22
From Proteopedia
(Difference between revisions)
| Line 6: | Line 6: | ||
Catechol oxidases (EC 1.10.3.1) catalyse the oxidation of o-diphenols to their corresponding o-quinones. These oxidases contain two copper ions (CuA and CuB) within the so-called coupled binuclear type-3 copper site as found in tyrosinases (EC 1.14.18.1) and haemocyanins. We determined the first crystal structure of a fungal catechol oxidase from ''Aspergillus oryzae'' (AoCO4). | Catechol oxidases (EC 1.10.3.1) catalyse the oxidation of o-diphenols to their corresponding o-quinones. These oxidases contain two copper ions (CuA and CuB) within the so-called coupled binuclear type-3 copper site as found in tyrosinases (EC 1.14.18.1) and haemocyanins. We determined the first crystal structure of a fungal catechol oxidase from ''Aspergillus oryzae'' (AoCO4). | ||
| - | Two different forms of AoCO4, called as a full-length and a truncated, were crystallized and the structures were solved at 2.5 and 2.9 Å resolution, respectively. The <scene name='55/559101/Cv/2'>overall structure of AoCO4</scene> is predominantly α-helical. A <span style="color:lime;background-color:black;font-weight:bold;">four-helix bundle forms the core (shown in green)</span> of the protein and the catalytic copper site is situated within this helical bundle. The truncated form lacks the <span style="color:cyan;background-color:black;font-weight:bold;">long N-terminal α-helix (shown in cyan)</span>, which is not part of the <span style="color:lime;background-color:black;font-weight:bold;">central helical bundle</span>. Both the full-length and truncated form exists as a similar transient dimer (surface area 855 Å<sup>2</sup>) in crystal. | + | Two different forms of AoCO4, called as a full-length and a truncated, were crystallized and the structures were solved at 2.5 and 2.9 Å resolution, respectively. The <scene name='55/559101/Cv/2'>overall structure of AoCO4</scene> is predominantly α-helical. A <span style="color:lime;background-color:black;font-weight:bold;">four-helix bundle forms the core (shown in green)</span> of the protein and the <scene name='55/559101/Cv/3'>catalytic copper site is situated within this helical bundle</scene>. The truncated form lacks the <span style="color:cyan;background-color:black;font-weight:bold;">long N-terminal α-helix (shown in cyan)</span>, which is not part of the <span style="color:lime;background-color:black;font-weight:bold;">central helical bundle</span>. Both the full-length and truncated form exists as a similar transient dimer (surface area 855 Å<sup>2</sup>) in crystal. |
The crystal structure of AoCO4 demonstrated that mono-oxygenase and diphenolase reactivity cannot be explained by accessibility to copper ions. Based on the observations that CuA is restricted by a Phe residue in plant catechol oxidases, but not in tyrosinases, it has been suggested that o-diphenols bind to CuB, whereas monophenols bind to CuA. However, both copper ions were solvent-exposed and accessible to substrates in AoCO4. | The crystal structure of AoCO4 demonstrated that mono-oxygenase and diphenolase reactivity cannot be explained by accessibility to copper ions. Based on the observations that CuA is restricted by a Phe residue in plant catechol oxidases, but not in tyrosinases, it has been suggested that o-diphenols bind to CuB, whereas monophenols bind to CuA. However, both copper ions were solvent-exposed and accessible to substrates in AoCO4. | ||
Revision as of 10:14, 17 September 2013
| |||||||||||
- ↑ REF
This page complements a publication in scientific journals and is one of the Proteopedia's Interactive 3D Complement pages. For aditional details please see I3DC.
