A Bifunctional Leader Peptidase/ABC Transporter Protein Is Involved in the Maturation of the Lasso Peptide Cochonodin I from Streptococcus suis

J Nat Prod. 2021 Oct 22;84(10):2683-2691. doi: 10.1021/acs.jnatprod.1c00514. Epub 2021 Oct 1.

Abstract

Lasso peptides are members of the natural product superfamily of ribosomally synthesized and post-translationally modified peptides (RiPPs). Here, we describe the first lasso peptide originating from a biosynthetic gene cluster belonging to a unique lasso peptide subclade defined by the presence of a bifunctional protein harboring both a leader peptidase (B2) and an ABC transporter (D) domain. Bioinformatic analysis revealed that these clusters also encode homologues of the NisR/NisK regulatory system and the NisF/NisE/NisG immunity factors, which are usually associated with the clusters of antimicrobial class I lanthipeptides, such as nisin, another distinct RiPP subfamily. The cluster enabling the heterologous production of the lasso peptide cochonodin I in E. coli originated from Streptococcus suis LSS65, and the threaded structure of cochonodin I was evidenced through extensive MS/MS analysis and stability assays. It was shown that the ABC transporter domain from SsuB2/D is not essential for lasso peptide maturation. By extensive genome mining dedicated exclusively to other lasso peptide biosynthetic gene clusters featuring bifunctional B2/D proteins, it was furthermore revealed that many bacteria associated with human or animal microbiota hold the biosynthetic potential to produce cochonodin-like lasso peptides, implying that these natural products might play roles in human and animal health.

MeSH terms

  • ATP-Binding Cassette Transporters / genetics*
  • Bacterial Proteins / genetics*
  • Computational Biology
  • Membrane Proteins / genetics*
  • Multigene Family
  • Protein Processing, Post-Translational
  • Serine Endopeptidases / genetics*
  • Streptococcus suis / genetics*

Substances

  • ATP-Binding Cassette Transporters
  • Bacterial Proteins
  • Membrane Proteins
  • Serine Endopeptidases
  • type I signal peptidase