Fungal metabolites. XXI. Characteristics of low energy collision induced dissociation of [M + 2H]2+, [M + H + Na]2+ and [M + 2Na]2+ of peptaibols using electrospray ionization mass spectrometry.

The mass spectral characteristics of selected peptaibols were investigated using electrospray ionization in conjunction with low-energy collision-induced dissociation (CID). Protonated and sodiated molecular species were selected as precursor ions and the resulting CID spectra are discussed with respect to fragmentation characteristics related to the structures of peptaibols. The CID spectra of peptaibols with acetylated N-terminus and with the sub-sequences of Aib-Pro were similar. The CID spectra of [M + 2Na]2+ provided structural information more than those of [M + 2H]2+ and [M + H + Na]2+. The CID of [M + 2Na]2+ can be used to deduce complete sequence information for peptaibols.