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Identification and Heterologous Expression of the sec-Dependent Bacteriocin Faerocin MK from Enterococcus faecium

Sorina Chiorean1, John C Vederas1, Marco J van Belkum2

  • 1Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada.

Probiotics and Antimicrobial Proteins
|January 8, 2018
PubMed

Insights

We identified and characterized faerocin MK, a novel class IIa bacteriocin from Enterococcus faecium M3K31. Faerocin MK exhibits broad-spectrum antimicrobial activity against Gram-positive bacteria.

Area of Science:

  • Microbiology
  • Biochemistry
  • Molecular Biology

Background:

  • Enterococcus faecium M3K31 genome sequencing revealed genes for three bacteriocins.
  • One of these is a SRCAM 602-like bacteriocin, now named faerocin MK.

Purpose of the Study:

  • To characterize the novel bacteriocin faerocin MK.
  • To investigate its antimicrobial activity and structural properties.
  • To analyze its genetic organization and secretion pathway.

Main Methods:

  • Chemical synthesis of faerocin MK and SRCAM 602.
  • Antimicrobial activity assays.
  • Spectroscopic analysis (circular dichroism) in trifluoroethanol.
  • Nucleotide sequence analysis of the faerocin MK operon.
  • Heterologous expression studies.

Main Results:

  • Faerocin MK is a 43-residue class IIa bacteriocin with YGNGV-motif and two cysteines.
  • Faerocin MK displays potent activity against Gram-positive organisms, unlike SRCAM 602.
  • Faerocin MK shows higher alpha-helical content than SRCAM 602.
  • The faerocin MK operon includes a signal peptide and an immunity gene.
  • Faerocin MK and its immunity protein are successfully expressed heterologously, indicating Sec pathway secretion.

Conclusions:

  • Faerocin MK is a novel, active class IIa bacteriocin with significant antimicrobial potential.
  • Its structure and secretion mechanism are elucidated.
  • Faerocin MK represents a promising candidate for antimicrobial applications.
Keywords:
BacteriocinsEnterococciProbioticsSRCAM peptidessec-dependent

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