Editing of the proteolytic system of Lactococcus lactis increases its bioactive potential

Chenxi Huang, Jan Kok*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

1 Citation (Scopus)
59 Downloads (Pure)

Abstract

Large-scale mass spectrometry-based peptidomics for bioactive-peptide discovery is relatively unexplored because of challenges in intracellular peptide extraction and small-peptide identification. Here, we present an analytical pipeline for large-scale intracellular peptidomics of Lactococcus lactis. It entails an optimized sample preparation protocol for L. lactis, used as an "enzyme complex" to digest γ-casein, an extraction method for its intracellular peptidome, and a peptidomics data analysis and visualization procedure. In addition, we proofread the publicly available bioactive-peptide databases and obtained an optimized database of bioactive peptides derivable from bovine γ-casein. We used the pipeline to examine cultures of L. lactis MG1363 and a set of 6 isogenic multiple peptidase mutants incubated with γ-casein. We observed a clearly strain-dependent accumulation of peptides with several bioactivities, such as angiotensin-converting enzyme (ACE)-inhibitory, dipeptidyl peptidase 4 (DPP-IV)-inhibitory, and immunoregulatory functions. The results suggest that both the number of different bioactive peptides and the bioactivity diversity can be increased by editing the proteolytic system of L. lactis. This comprehensive pipeline offers a model for discovery of bioactive peptides in combination with other proteins and might be applicable to other bacteria.

Original languageEnglish
Article numbere01319
Number of pages18
JournalApplied and environmental microbiology
Volume86
Issue number18
Early online date17-Jul-2020
DOIs
Publication statusPublished - 1-Sep-2020

Keywords

  • Bioactive peptides
  • Intracellular peptidomics
  • Lactococcus lactis
  • Proteolytic system

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