A hybrid non-ribosomal peptide/polyketide synthetase containing fatty-acyl ligase (FAAL) synthesizes the β-amino fatty acid lipopeptides puwainaphycins in the Cyanobacterium Cylindrospermum alatosporum

PLoS One. 2014 Nov 4;9(11):e111904. doi: 10.1371/journal.pone.0111904. eCollection 2014.

Abstract

A putative operon encoding the biosynthetic pathway for the cytotoxic cyanobacterial lipopeptides puwainphycins was identified in Cylindrospermum alatosporum. Bioinformatics analysis enabled sequential prediction of puwainaphycin biosynthesis; this process is initiated by the activation of a fatty acid residue via fatty acyl-AMP ligase and continued by a multidomain non-ribosomal peptide synthetase/polyketide synthetase. High-resolution mass spectrometry and nuclear magnetic resonance spectroscopy measurements proved the production of puwainaphycin F/G congeners differing in FA chain length formed by either 3-amino-2-hydroxy-4-methyl dodecanoic acid (4-methyl-Ahdoa) or 3-amino-2-hydroxy-4-methyl tetradecanoic acid (4-methyl-Ahtea). Because only one puwainaphycin operon was recovered in the genome, we suggest that the fatty acyl-AMP ligase and one of the amino acid adenylation domains (Asn/Gln) show extended substrate specificity. Our results provide the first insight into the biosynthesis of frequently occurring β-amino fatty acid lipopeptides in cyanobacteria, which may facilitate analytical assessment and development of monitoring tools for cytotoxic cyanobacterial lipopeptides.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics*
  • Bacterial Proteins / physiology
  • Biosynthetic Pathways
  • Cyanobacteria / enzymology*
  • Cyanobacteria / genetics
  • Genes, Bacterial
  • Ligases / genetics*
  • Ligases / physiology
  • Lipopeptides / biosynthesis
  • Molecular Sequence Annotation
  • Molecular Sequence Data
  • Multigene Family
  • Polyketide Synthases / genetics*
  • Polyketide Synthases / physiology

Substances

  • Bacterial Proteins
  • Lipopeptides
  • puwainaphycin F
  • puwainaphycin G
  • Polyketide Synthases
  • Ligases

Associated data

  • BioProject/PRJNA261005
  • GENBANK/KM078884

Grant support

This study was supported by the Grant Agency of the Czech Republic, project “Toxic potential, Evolution of Toxin Synthesis and Factors Driving Anatoxin-a Production in Benthic and Soil Nostocacean Cyanobacteria” (No. 14-18067S) and by the Center for Algal Biotechnology Třeboň - ALGATECH (CZ. 1.05/21.00/03.0110). The NMR experiments were performed at the Upper Austrian - South Bohemian Research Infrastructure Center in Linz, co-financed by the European Union in the context of the project “RERI-uasb”, EFRE RU2-EU-124/100-2010 (ETC Austria-Czech Republic 2007–2013, project M00146). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.