Unearthing a Cryptic Biosynthetic Gene Cluster for the Piperazic Acid-Bearing Depsipeptide Diperamycin in the Ant-Dweller sp. CS113.

Piperazic acid is a cyclic nonproteinogenic amino acid that contains a hydrazine N-N bond formed by a piperazate synthase (KtzT-like). This amino acid, found in bioactive natural products synthesized by non-ribosomal peptide synthetases (NRPSs), confers conformational constraint to peptides, an important feature for their biological activities. Genome mining of strains has been revealed as a strategy to identify biosynthetic gene clusters (BGCs) for potentially active compounds.

Novel Bioactive Paulomycin Derivatives Produced by Streptomyces albus J1074.

Four novel paulomycin derivatives have been isolated from J1074 grown in MFE culture medium. These compounds are structural analogs of antibiotics 273a and 273a containing a thiazole moiety, probably originated through an intramolecular Michael addition. The novel, thiazole, moiety-containing paulomycins show a lower antibiotic activity than paulomycins A and B against Gram-positive bacteria.