Park Ju-Wan, Kang Hyeon-Woo, Ha Byung-Suk, Kim Sin-Il, Kim Soonok, Ro Hyeon-Su
Division of Applied Life Science and Research Institute for Life Science, Gyeongsang National University, Jinju, 660-701, Korea.
Arch Microbiol. 2015 May;197(4):589-96. doi: 10.1007/s00203-015-1090-7. Epub 2015 Feb 13.
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.
研究了铜离子（Cu(2+)）对从韩国不同地区采集的7种不同的朱红密孔菌菌株漆酶活性和表达的影响。在液体培养中，当CuSO4浓度大于0.5 mM时，Cu(2+)对菌丝体生长有毒性，在1 mM时表现出完全生长抑制。然而，在0.2 mM时，Cu(2+)显著上调了5种朱红密孔菌菌株（IUM4209、IUM0032、IUM0450、IUM0470和IUM4093）的胞外漆酶活性，而另外两种菌株IUM0253和IUM0049，尽管与其他5种菌株密切相关，但对Cu(2+)没有反应。随后的RT-PCR分析还表明，仅在前5种菌株中，在Cu(2+)存在的情况下漆酶mRNA高度表达。综上所述，这些结果表明Cu(2+)以菌株依赖的方式调节漆酶基因的表达。这5种菌株通常产生一种分子量为68 kDa的单一主要漆酶蛋白。肽测序显示该漆酶是在中国分离的朱红密孔菌Lcc1的同源物。Cu(2+)诱导的培养上清液对多环芳烃表现出高度降解，表明68 kDa漆酶是朱红密孔菌主要的胞外降解酶。
