Cloning and expression of a cDNA encoding the laccase from schizophyllum commune

We cloned and analyzed the nucleotide sequence of a cDNA that encodes polyphenol oxidase (laccase) from the white-rot basidiomycete Schizophyllum commune.The nucleotide sequence of the full-length cDNA contained a1554-base open reading frame that encoded a polypeptide of 518 amino acid residues, including a putative signal peptide of 16 residues. It contained four highly similar regions that are conserved in the deduced amino acid sequences of otherlaccases, including the region thought to be involved in copper binding.Aspergillus sojae strain 1860 (which has low protease levels) was transformed with the plasmid lacAL/pTPT, which contained the laccase gene under the control of the tannase promoter fromAspergillus oryzae. Laccase was secreted into the medium when transformants A1 and A2 were cultured in tannic acid-containing medium.