[Study on conformation transitions of trichokonin VI, a peptaibol-like antimicrobial peptide, in different solvents by circular dichroism spectroscopy].

Trichokonin VI, a peptaibol-like antimicrobial peptides isolated from the cultured substrates of trichoderma koningii SMF2, has 20 amino acid residues. The conformational flexibility of trichokonin VI in organic solvents with different polarities, aqueous solvents and membrane mimic solvents was studied by circular dichroism spectroscopy. Trichokonin VI takes on a typical alpha-helical structure in different organic solvents, but helicity decreases in aqueous solvent. The helical content increases with increasing the concentration of TFE up to 30%. In phosphate buffered saline, the CD spectrum of trichokonin VI is concentration dependent, and the intensity of the peaks increases with increasing the concentration of trichokonin VI. SDS induces a significant transition towards a helix formation, and the CD spectra in membrane mimic solvents increase helicity compared with those recorded without membrane mimic solvents, suggesting the interaction of the peptides with the membrane.