title: Strain-dependent response to Cu(2+) in the expression of laccase in Pycnoporus coccineus.
abstract: The effects of Cu(2+) on the activity and expression of laccase were investigated in seven different strains of Pycnoporus coccineus collected from different regions in Korea. Cu(2+) was toxic to mycelial growth at concentrations greater than 0.5 mM CuSO4 and showed complete growth inhibition at 1 mM in the liquid culture. However, Cu(2+) significantly upregulated the extracellular laccase activity at 0.2 mM in five strains of P. coccineus, IUM4209, IUM0032, IUM0450, IUM0470, and IUM4093, whereas two strains, IUM0253 and IUM0049, did not respond to Cu(2+), despite being closely related to the other five strains. Subsequent RT-PCR analysis also showed that the laccase mRNA was highly expressed only in the former five strains in the presence of Cu(2+). Taken together, these results indicate that Cu(2+) regulates expression of the laccase gene in a strain-dependent manner. The five strains commonly produced a single predominant laccase protein with a molecular weight of 68 kDa. Peptide sequencing revealed that the laccase was a homolog of Lcc1 of P. coccineus, which was isolated in China. The Cu(2+)-induced culture supernatants exhibited high degradation of polycyclic aromatic hydrocarbons, indicating that the 68-kDa laccase is the primary extracellular degradative enzyme in P. coccineus.
authors: Division of Applied Life Science and Research Institute for Life Science, Gyeongsang National University, Jinju, 660-701, Korea.
authors: Ju-Wan
authors: JW
authors: Park
authors: Hyeon-Woo
authors: HW
authors: Kang
authors: Byung-Suk
authors: BS
authors: Ha
authors: Sin-Il
authors: SI
authors: Kim
authors: Soonok
authors: S
authors: Kim
authors: Hyeon-Su
authors: HS
authors: Ro
mesh_terms: D000595:Amino Acid Sequence; D002681:China; D019327:Copper Sulfate / Q000494:pharmacology*; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects*; D042845:Laccase / Q000235:genetics / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism; D055494:Pycnoporus / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D056910:Republic of Korea; D016415:Sequence Alignment
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D042845:Laccase; D019327:Copper Sulfate