Identification of Cyclic Depsipeptides and Their Dedicated Synthetase from Hapsidospora irregularis

J Nat Prod. 2017 Feb 24;80(2):363-370. doi: 10.1021/acs.jnatprod.6b00808. Epub 2017 Jan 20.

Abstract

Seven cyclic depsipeptides were isolated from Hapsidospora irregularis and structurally characterized as the calcium channel blocker leualacin and six new analogues based on the NMR and HRESIMS data. These new compounds were named leualacins B-G. The absolute configurations of the amino acids and 2-hydroxyisocaproic acids were determined by recording the optical rotation values. Biological studies showed that calcium influx elicited by leualacin F in primary human lobar bronchial epithelial cells involves the TRPA1 channel. Through genome sequencing and targeted gene disruption, a noniterative nonribosomal peptide synthetase was found to be involved in the biosynthesis of leualacin. A comparison of the structures of leualacin and its analogues indicated that the A2 and A4 domains of the leualacin synthetase are substrate specific, while A1, A3, and A5 can accept alternative precursors to yield new molecules.

Publication types

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

MeSH terms

  • Amino Acids / chemistry
  • Calcium Channel Blockers / chemistry
  • Depsipeptides / chemistry
  • Depsipeptides / isolation & purification*
  • Depsipeptides / pharmacology
  • Humans
  • Hypocreales / chemistry*
  • Molecular Structure
  • Nuclear Magnetic Resonance, Biomolecular
  • Peptide Synthases / metabolism*
  • Peptides, Cyclic

Substances

  • Amino Acids
  • Calcium Channel Blockers
  • Depsipeptides
  • Peptides, Cyclic
  • leualacin
  • Peptide Synthases