Laccase

Function

Laccase (Lac) or multicopper oxidase is a multi-copper protein which uses molecular oxygen to oxidize various aromatic and non-aromatic compounds by a radical-catalyzed reaction mechanism^[1]. Laccase 2 (Lac2) acts in lignin degradation and in detoxification of lignin products. Typically, laccases show a three cupredoxin-domain folding^[2]. Two-domain laccase or small lactase have unusual resistance to inhibitors^[3]. CotA laccase belongs to the multi-copper oxidase family. The multi-copper oxidases constitute a family of enzymes whose principal members are laccase (benzenediol oxygen oxidoreductase, EC 1.10.3.2), ascorbate oxidase (L-ascorbate oxygen oxidoreductase, EC 1.10.3.3) and ceruloplasmin (Fe(II) oxygen oxidoreductase, EC 1.16.3.1). Similar to the other laccases the three dimensional structure of CotA 1w6l comprises three cupredoxin domains and four copper ions organised in : a and .^[4][5]

For laccase with nitrotyrosine modification see Nitrotyrosine.

Relevance

Laccase from various fungi is used in adsorption of dyes from polluted environment</ref>^[6]. Laccases play an important role in food industry, paper and pulp industry, textile industry, synthetic chemistry, cosmetics, soil bioremediation and biodegradation of phenolic pollutants^[7].

Structural highlights

The trinuclear center of CotA laccase has two type 3 copper ions, that can be anti-ferromagnetically coupled through an hydroxyl moiety in between them, and one type 2 copper ion.‡ The mononuclear copper is able to accept an electron from a variety of phenolic substrates and then transmit it to the trinuclear centre.

3D structures of laccase

Laccase 3D structures