The laccase gene family in Coprinopsis cinerea (Coprinus cinereus)

In this study, we isolated and sequenced eight non-allelic laccase genes from Coprinopsis cinerea (Coprinus cinereus) homokaryon AmutBmut. These eight genes represent the largest laccase gene family identified so far in a single haploid fungal genome. We analyzed the phylogenetic relationships between these genes by intron positions, amino acid sequence conservation and similarities in promoter sequences. All deduced protein products have the laccase signature sequences L1–L4, the typical conserved cysteine and the ten histidine residues which are ligands in the two laccase copper-binding centers, T1 and T2/T3. Proteins Lcc2 and Lcc3 of Coprinopsis cinerea are most similar to the acidic, membrane-associated laccase CLAC2 from Coprinellus congregatus implicated in neutralization of acidic medium. All other laccases from the saprophyte Coprinopsis cinerea, including the well described enzyme Lcc1, form a cluster separate from these three enzymes and from various laccases of wood-rotting and plant-pathogenic basidiomycetes.