Recombinant laccase from Pediococcus acidilactici CECT 5930 with ability to degrade tyramine

PLoS One. 2017 Oct 11;12(10):e0186019. doi: 10.1371/journal.pone.0186019. eCollection 2017.

Abstract

Biogenic amines degradation by bacterial laccases is little known, so we have cloned and heterologously expressed, in E. coli, a new laccase from Pediococcus acidilactici CECT 5930 (Lpa5930), a lactic acid bacterium commonly found in foods able to degrade tyramine. The recombinant enzyme has been characterized by physical and biochemical assays. Here we report the optimization of expression and purification procedures of this laccase. DNA encoding sequence of laccase from P. acidilactici was amplified by PCR and cloned into the expression plasmid pET28a for induction by isopropyl-β-D-thiogalactoipyranoside. Protein expression was performed in E. coli BL21(DE3) harboring pGro7 plasmid expressing a chaperone folding assistant induced by arabinose. Purification was performed by column metal-chelating chromatography on Ni-NTA-agarose. The laccase enzyme obtained has an apparent molecular mass of ∼60 kDa, an optimum temperature activity toward 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) of 28°C, and was quickly inactivated at temperatures higher than 70°C. The apparent Km value for ABTS was 1.7 mM and the Vmax obtained was 24 U/mg. In addition to ABTS, recombinant Lpa5930 laccase degraded the biogenic amine tyramine at pH 9.5 and pH 4.0 with or without ABTS as a mediator. Tyramine degradation by laccases could solve the problems generated in food due to the presence of this toxic compound.

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / chemistry
  • Base Sequence
  • Benzothiazoles / metabolism
  • Cloning, Molecular
  • Electrophoresis, Polyacrylamide Gel
  • Hydrogen-Ion Concentration
  • Laccase / metabolism*
  • Oxidation-Reduction
  • Pediococcus acidilactici / enzymology*
  • Recombinant Proteins / isolation & purification*
  • Recombinant Proteins / metabolism
  • Sequence Analysis, DNA
  • Spectrophotometry, Ultraviolet
  • Substrate Specificity
  • Sulfonic Acids / metabolism
  • Temperature
  • Tyramine / metabolism*

Substances

  • Bacterial Proteins
  • Benzothiazoles
  • Recombinant Proteins
  • Sulfonic Acids
  • 2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid
  • Laccase
  • Tyramine

Grants and funding

The present work has been partially financed by Project AGL2015-71227-R from European Regional Development Fund and the Spanish Ministerio de Economía y Competitividad (http://www.mineco.gob.es/portal/site/mineco/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.