A "yellow" laccase with "blue" spectroscopic features, from Sclerotinia sclerotiorum

Mot, A. C. and Parvu, M. and Damian, G. and Irimie, F. D. and Darula, Zsuzsanna and Medzihradszky F., Katalin and Brem, Balázs (2012) A "yellow" laccase with "blue" spectroscopic features, from Sclerotinia sclerotiorum. PROCESS BIOCHEMISTRY, 47 (6). pp. 968-975. ISSN 1359-5113

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Abstract

Reported here are the production, purification and characterization of a laccase from the phytophathogenic fungus Sclerotinia sclerotiorum. This laccase is identified by mass spectrometry with a sequence coverage of 74.9% (458/577 AA) revealing that the protein is identical or highly homologous to a predicted oxidoreductase from this species (A7EM18 in the Uniprot database); the closest homologous protein previously isolated from a fungus is the Melanocarpus albomyces, with only 35% identity. The UV-vis spectral features of this laccase classify it as a "yellow" one. The EPR spectrum nevertheless demonstrates resemblance to blue laccases - including the type 1 center not detectable in UV-vis spectra. The presence of type 3 coppers was proven by fluorescence spectrum and by 330 nm band in UV-vis. The purified laccase has an apparent molecular mass of 70 kDa and appears as a monomer. The values of K-M and k(cat) were determined for ABTS, 2,6-dimethoxyphenol, p-phenylenediamine and guaicol and are typical of a laccase. The optimal pH value is around 4 except for ABTS, for which activity is linearly increasing with acidity. The high laccase activity in liquid culture makes S. sclerotiorum a useful source of laccase for practical applications. (C) 2012 Elsevier Ltd. All rights reserved.

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