The circular bacteriocin enterocin NKR-5-3B has an improved stability profile over nisin

Conan K. Wang, Yen Hua Huang, Fatima Shabbir, Huong T. Pham, Nicole Lawrence, Aurélie H. Benfield, Wilfred van der Donk, Sónia T. Henriques, Mark S. Turner, David J. Craik

Research output: Contribution to journalArticlepeer-review

Abstract

Bacteriocins are a large family of bacterial peptides that have antimicrobial activity and potential applications as clinical antibiotics or food preservatives. Circular bacteriocins are a unique class of these biomolecules distinguished by a seamless circular topology, and are widely assumed to be ultra-stable based on this constraining structural feature. However, without quantitative studies of their susceptibility to defined thermal, chemical, and enzymatic conditions, their stability characteristics remain poorly understood, limiting their translational development. Here, we produced the circular bacteriocin enterocin NKR-5-3B (Ent53B) in mg/L quantities using a heterologous Lactococcus expression system, and characterized its thermal stability by NMR, chemical stability by circular dichroism and analytical HPLC, and enzymatic stability by analytical HPLC. We demonstrate that Ent53B is ultra-stable, resistant to temperatures approaching boiling, acidic (pH 2.6) and alkaline (pH 9.0) conditions, the chaotropic agent 6 M urea, and following incubation with a range of proteases (i.e., trypsin, chymotrypsin, pepsin, and papain), conditions under which most peptides and proteins degrade. Ent53B is stable across a broader range of pH conditions and proteases than nisin, the most widely used bacteriocin in food manufacturing. Antimicrobial assays showed that differences in stability correlated with differences in bactericidal activity. Overall, this study provides quantitative support for circular bacteriocins being an ultra-stable class of peptide molecules, suggesting easier handling and distribution options available to them in practical applications as antimicrobial agents.

Original languageEnglish (US)
Article number171049
JournalPeptides
Volume167
DOIs
StatePublished - Sep 2023

Keywords

  • Antimicrobial peptide
  • Stability

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Endocrinology
  • Cellular and Molecular Neuroscience

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