Roads to Rome: Role of Multiple Cassettes in Cyanobactin RiPP Biosynthesis

J Am Chem Soc. 2018 Nov 28;140(47):16213-16221. doi: 10.1021/jacs.8b09328. Epub 2018 Nov 14.

Abstract

Ribosomally synthesized and post-translationally modified peptides (RiPPs) are ubiquitous natural products. Bioactive RiPPs are produced from a precursor peptide, which is modified by enzymes. Usually, a single product is encoded in a precursor peptide. However, in cyanobactins and several other RiPP pathways, a single precursor peptide encodes multiple bioactive products flanking with recognition sequences known as "cassettes". The role of multiple cassettes in one peptide is mysterious, but in general their presence is a marker of biosynthetic plasticity. Here, we show that in cyanobactin biosynthesis the presence of multiple cassettes confers distributive enzyme processing to multiple steps of the pathway, a feature we propose to be a hallmark of multicassette RiPPs. TruD heterocyclase is stochastic and distributive. Although a canonical biosynthetic route is favored with certain substrates, every conceivable biosynthetic route is accepted. Together, these factors afford greater plasticity to the biosynthetic pathway by equalizing the processing of each cassette, enabling access to chemical diversity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkylation
  • Amino Acid Sequence
  • Cyclization
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / metabolism
  • Intramolecular Transferases / chemistry
  • Intramolecular Transferases / metabolism
  • Peptides, Cyclic / biosynthesis*
  • Peptides, Cyclic / chemistry
  • Peptides, Cyclic / metabolism
  • Protein Domains
  • Protein Precursors / chemistry
  • Protein Precursors / metabolism*
  • Protein Processing, Post-Translational
  • Stochastic Processes
  • Substrate Specificity

Substances

  • Escherichia coli Proteins
  • Peptides, Cyclic
  • Protein Precursors
  • cyanobactins
  • Intramolecular Transferases
  • TruD protein, E coli