Primary structure and transcription analysis of a laccase-encoding gene from the basidiomycete Trametes trogii

A cDNA coding for laccase was isolated from the white-rot fungus Trametes trogii 201. This cDNA corresponded to the lcc1 gene, which coded for a precursor protein of 517 amino acids with a 21 amino acid signal peptide. Comparison of the deduced sequence with known laccases showed that this enzyme was most closely related to Lac1 from basidiomycete PM1 and Trametes C30 (98% similarity). The expression of lcc1 was analysed under different growth conditions; transcription of this gene was enhanced by the addition of organic nitrogen to the medium. The level of lcc1 transcription was higher when T. trogii was grown on synthetic medium supplemented with yeast extract rather than mycological peptone or tryptone. The transcription data were in agreement with total laccase activity measured in the supernatant and suggested that laccase production and lcc1 transcription are coordinately regulated in this organism. The lcc1 cDNA was expressed in the methylotrophic yeast Pichia pastoris and the detection of laccase activity indicated that this cDNA encodes a laccase.