Nuclear magnetic resonance study and secondary structure determination of the antibiotic peptide, aibellin

Aibellin is a 20-residue peptide antibiotic that has been isolated from the fungus Verticimonosporium ellipticum. Sequence-specific assignment of the 1H- and 13C-NMR signals of aibellin in a methanol solution was achieved by using the two-dimensional NMR technique. Furthermore, its secondary structure was characterized by circular dichroism (CD) and NOESY spectra. The observed NOEs, 3JNHC alpha H coupling constants and amide hydrogen-deuterium (H-D) exchange rates show that the peptide consisted of two alpha-helices and a bent structure around a Pro-14 residue.

Structural elucidation of aibellin, a new peptide antibiotic with efficiency enhancing activity on rumen fermentation

A new peptide antibiotic, aibellin, that had the efficiency enhancing activity on rumen fermentation, was isolated from the culture broth of the fungus, Verticimonosporium ellipticum D1528, and its primary structure was elucidated from spectrometric analysis and chemical degradation. Aibellin is a 20-residue peptaibol, and it has a unique structural feature in the novel C-terminal amino alcohol. Moreover, aibellin is the first peptaibol that possesses two acidic amino acids in the C-terminal region and a Phe residue in the middle of the sequence.