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Dissociation of deprotonated microcystin variants by collision‐induced dissociation following electrospray ionization
Author(s) -
Dörr Felipe Augusto,
OliveiraSilva Diogo,
Lopes Norberto Peporine,
Iglesias Jacobo,
Volmer Dietrich A.,
Pinto Ernani
Publication year - 2011
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.5083
Subject(s) - chemistry , fragmentation (computing) , dissociation (chemistry) , mass spectrometry , collision induced dissociation , mass spectrum , protonation , deprotonation , orbitrap , electrospray ionization , ion , electrospray , analytical chemistry (journal) , tandem mass spectrometry , chromatography , organic chemistry , computer science , operating system
Microcystins (MC) are a family of hepatotoxic cyclic heptapeptides produced by a number of different cyanobacterial species. Considering the recent advances in the characterization of deprotonated peptides by mass spectrometry, the fragmentation behavior of four structurally related microcystin compounds was investigated using collision‐induced dissociation (CID) experiments on an orbitrap mass spectrometer. It is demonstrated in this study that significant structural information can be obtained from the CID spectra of deprotonated microcystins. A predominant ring‐opening reaction at the iso MeAsp residue, as well as two major complementary fragmentation pathways, was observed, reducing the complexity of the product ion spectra in comparison with spectra observed from protonated species. This proposed fragmentation behavior was applied to characterize [Leu 1 ]MC‐LR from a cyanobacterial cell extract. In conclusion, CID spectra of microcystins in the negative ion mode provide rich structurally informative mass spectra which greatly enhance confidence in structural assignments, in particular when combined with complementary positive ion CID spectra. Copyright © 2011 John Wiley & Sons, Ltd.