MOLECULAR ANALYSIS OF A LACCASE GENE FROM THE WHITE-ROT FUNGUS PYCNOPORUS-CINNABARINUS

It was recently shown that the white rot basidiomycete Pycnoporus cinn abarinus secretes an unusual set of phenoloxidases when it is grown un der conditions that stimulate ligninolysis (C. Eggert, U. Temp, and K. -E. L. Eriksson, Appl. Environ. Microbiol. 62:1151-1158, 1996), In thi s report we describe the results of a cloning and structural analysis of the laccase-encoding gene (lcc3-1) expressed by P. cinnabarinus dur ing growth under xylidine-induced conditions. The coding region of the genomic laccase sequence, which is preceded by the eukaryotic promote r elements TATA and CAATA, spans more than 2,390 bp. The corresponding laccase cDNA was identical to the genomic sequence except for 10 intr ons that were 50 to 60 bp long. A sequence analysis indicated that the P. cinnabarinus lcc3-1 product has a Phe residue at a position likely to influence the reduction-oxidation potential of the enzyme's type 1 copper center. The P. cinnabarinus lcc3-1 sequence was most similar t o the sequence encoding a laccase from Coriolus hirsutus (level of sim ilarity, 84%).