1kya

From Proteopedia

---

Revision as of 00:03, 25 November 2007

proteopedia linkproteopedia link

spinqualitylabelsall models 1kya, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

ACTIVE LACCASE FROM TRAMETES VERSICOLOR COMPLEXED WITH 2,5-XYLIDINE

Overview

Laccases are multicopper oxidases that catalyze the oxidation of a wide, range of phenols or arylamines, and their use in industrial oxidative, processes is increasing. We purified from the white rot fungus Trametes, versicolor a laccase that exists as five different isozymes, depending on, glycosylation. The 2.4 A resolution structure of the most abundant isozyme, of the glycosylated enzyme was solved. The four copper atoms are present, and it is the first crystal structure of a laccase in its active form. The, crystallized enzyme binds 2,5-xylidine, which was used as a laccase, inducer in the fungus culture. This arylamine is a very weak reducing, substrate of the enzyme. The cavity enclosing 2,5-xylidine is rather wide, allowing the accommodation of substrates of various sizes. Several amino, acid residues make hydrophobic interactions with the aromatic ring of the, ligand. In addition, two charged or polar residues interact with its amino, group. The first one is an histidine that also coordinates the copper that, functions as the primary electron acceptor. The second is an aspartate, conserved among fungal laccases. The purified enzyme can oxidize various, hydroxylated compounds of the phenylurea family of herbicides that we, synthesized. These phenolic substrates have better affinities at pH 5 than, at pH 3, which could be related to the 2,5-xylidine binding by the, aspartate. This is the first high-resolution structure of a multicopper, oxidase complexed to a reducing substrate. It provides a model for, engineering laccases that are either more efficient or with a wider, substrate specificity.

About this Structure

1KYA is a Single protein structure of sequence from Trametes versicolor with NAG, CU, PYE and XYD as ligands. Active as Laccase, with EC number 1.10.3.2 Full crystallographic information is available from OCA.

Reference

Crystal structure of a four-copper laccase complexed with an arylamine: insights into substrate recognition and correlation with kinetics., Bertrand T, Jolivalt C, Briozzo P, Caminade E, Joly N, Madzak C, Mougin C, Biochemistry. 2002 Jun 11;41(23):7325-33. PMID:12044164

Page seeded by OCA on Sun Nov 25 02:10:32 2007