A series of new metallophores, referred to as frankobactins, were extracted from cultures of the symbiotic and nitrogen-fixing actinobacterium Frankia sp. CH37. Structure elucidation revealed a 2-hydroxyphenyl-substituted oxazoline core and a chain composed of five proteinogenic and nonproteinogenic amino acids, suggesting nonribosomal peptide synthesis as the biosynthetic origin. By whole-genome sequencing, bioinformatic analysis, and comparison with other Frankia strains, the genetic locus responsible for the biosynthesis was detected. Spectrophotometric titration of frankobactin with Fe(III) and Cu(II) and mass spectrometry established the 1:1 (metal:frankobactin) coordination. Uptake experiments suggested that frankobactin A1 (1) did not serve to recruit iron, but to detoxify Cu(II). As frankobactin A1 prevents the cellular entry of Cu(II), it could play a crucial role in the symbiosis of Frankia sp. and its host in the reclamation of copper-contaminated soil.
PubMed ID: 33789052
Publication type: Journal
Journal: J Nat Prod
Citation: J Nat Prod. 2021 Apr 23;84(4):1216-1225. doi: 10.1021/acs.jnatprod.0c01291. Epub 2021 Mar 31.
Date Published: 23rd Apr 2021
Registered Mode: by PubMed ID
Created: 10th May 2021 at 14:03