Purification and biochemical characterization of a laccase from the aquatic fungus Myrioconium sp. UHH 1-13-18-4 and molecular analysis of the laccase-encoding gene

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • C. Martin - , Helmholtz Centre for Environmental Research (Author)
  • M. Pecyna - , Helmholtz Centre for Environmental Research (Author)
  • H. Kellner - , Leipzig University (Author)
  • N. Jehmlich - , Helmholtz Centre for Environmental Research (Author)
  • C. Junghanns - , Helmholtz Centre for Environmental Research (Author)
  • D. Benndorf - , Helmholtz Centre for Environmental Research (Author)
  • M. Von Bergen - , Helmholtz Centre for Environmental Research (Author)
  • D. Schlosser - , Helmholtz Centre for Environmental Research (Author)

Abstract

Myrioconium sp. strain UHH 1-13-18-4 is an ascomycete anamorph isolated from the river Saale, Central Germany. An extracellular, monomeric, and glycosylated laccase with a molecular mass of 72.7 kDa as determined by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry and an isoelectric point below 2.8 was purified from CuSO4 and vanillic acid amended liquid fungal cultures grown in malt extract medium. The catalytic efficiencies (k cat/K m) for the oxidation of syringaldazine, 2,6-dimethoxyphenol, and 2,2′-azino-bis(3- ethylbenzthiazoline-6-sulfonate) were 67.3, 46.9, and 28.2 s-1 mM-1, respectively, with K m values of 4.2, 67.8, and 104.9 μM. After pre-incubation at different pH values and temperatures for 1 h, more than 80% of the initial laccase activity was retained between pH 4 to 6 and 15°C. The laccase-encoding gene was identified and sequenced at both the genomic and complementary DNA (cDNA) level, and corresponding structural characteristics and putative regulatory elements of the promoter region are reported. The identification of two tryptic peptides of the purified enzyme by mass spectrometry confirmed the identity of the functional laccase protein with the translated genomic sequence of the Myrioconium sp. laccase. Myrioconium sp. laccase shows the highest degree of identity with laccases from ascomycetes belonging to the family Sclerotiniaceae, order Helotiales.

Details

Original languageEnglish
Pages (from-to)613-624
Number of pages12
JournalApplied Microbiology and Biotechnology
Volume77
Issue number3
Publication statusPublished - Nov 2007
Peer-reviewedYes
Externally publishedYes

External IDs

PubMed 17955194

Keywords

Keywords

  • Aquatic fungi, Ascomycete, Characterization, Expression, Gene, Laccase