Arylomycins A and B, new biaryl-bridged lipopeptide antibiotics produced by Streptomyces sp. Tü 6075. II. Structure elucidation.

The structures of new lipopeptide antibiotics, arylomycins A and B, were elucidated by a combination of ESI-FTICR-mass spectrometry, NMR spectroscopy, Edman sequencing, and fatty acid and chiral amino acid analyses. The colourless arylomycins A share the peptide sequence of D-N-methylseryl2(D-MeSer2)-D-alanyl3-glycyl4-N-methyl- 4-hydroxyphenylglycyl5(MeHpg5)-L-alanyl6-tyrosine7 cyclised by a [3,3]biaryl bond between MeHpg5 and Tyr7. The yellow arylomycins B differ from arylomycins A by nitro substitution of Tyr7. The N-termini of arylomycins A and B are acylated with saturated C11-C15 fatty acids (fa1) comprising n, iso, and anteiso isomers. Arylomycins A and B represent the first examples of biaryl-bridged lipopeptides.