# Salamandamide Lipodipeptides Are Biosynthetic Intermediate Shunt Products of the Nonamodular Nonribosomal Peptide Assembly Lines of the Viscosin Family

## TL;DR

A new lipo-dipeptide, salamandamide A, was found to be a byproduct of a known biosynthetic pathway in Pseudomonas bacteria.

## Contribution

The study reveals that lipo-dipeptides like salamandamide A are shunt products of nonamodular NRPS gene clusters in the viscosin family.

## Key findings

- Salamandamide A is biosynthesized via the NRPS gene cluster of pseudodesmin.
- Lipo-dipeptides are shunt products of nonamodular NRPS gene clusters in the viscosin family.
- Salamandamide B was discovered as a related compound from Pseudomonas lactis.

## Abstract

Chemical
investigation of a salamander-mucus-associated Pseudomonas
tolaasii strain led to the isolation and chemical
characterization of salamandamide A, a new lipo-dipeptide, along with
known lipopeptides of the pseudodesmin and tolaasin class. Genome
mining revealed that no specific gene cluster codes for the biosynthesis
of salamandamide A. Stereochemical analyses and mutagenesis experiments
linked the biosynthesis of the lipo-dipeptide salamandamide A to the
NRPS gene cluster of the lipo-nonapeptide pseudodesmin. Further chemical
investigations showed that this finding appears to be a broader concept
and that all nonamodular NRPS gene clusters of the viscosin family
were capable to produce, beside the expected lipo-nonapeptide, the
corresponding lipo-dipeptide as a shunt product which also led to
the discovery of salamandamide B from Pseudomonas lactis SS101.