Tyrocidine A interactions with saccharides investigated by CD and NMR spectroscopies.

摘要: Tyrocidines are a family of cyclic decapeptides produced by the soil bacterium, Brevibacillus parabrevis. These antibiotic peptides can be used to prevent infections in agriculture and food industry but also prepare antimicrobial lozenges, creams, dressings for medical applications. It has been observed that tyrocidines interact with saccharides such as cellulose from their environment, well sugars culture media glycans fungal cell walls. Here, we investigated interactions glucose, sucrose, cellotetraose (as model) quantitative fashion utilising CD NMR spectroscopy. The spectra tyrocidine A (TrcA) were analysed function solvent composition, spectral properties agree formation oligomeric structures governed β-sheet secondary once acetonitrile content is increased. Saccharides seem induce TrcA changes reverting those induced organic solvents. presence glucose new ordered H-bonding, possibly structures. amides involved intramolecular H-bonding remained largely unaffected environmental changes. In contrast, exposed exterior and/or intermolecular association show largest 1 H chemical shift spectroscopic investigations correlated TrcA-glucose characterized dissociation constant around 200 μM. Interestingly, corresponds closely additive effect four moieties, while much higher was sucrose. Similar trends binding three analogous tyrocidines, B, C. results therefore indicate monosaccharide unit fairly specific reversible.