Mass spectrometric fragmentation of cyclic peptides belonging to the polymyxin and colistin antibiotics studied by ion trap and quadrupole/orthogonal-acceleration time-of-flight technology.
Electrospray ionization linked to quadrupole/orthogonal-acceleration time-of-flight (Q/oaTOF) and ion trap equipment was used to study the fragmentation behavior of the linear side-chain cyclized peptides of the polymyxin B and E antibiotics. This study exemplifies both the benefits and the drawbacks of mass spectrometric techniques for the determination of the sequence of such complex linear side-chain cyclized peptides. Q/oaTOF accurate mass measurements did not help sufficiently to assign the product ions observed in the product ion spectra. An ion trap mass spectrometer providing MS(n) capability was used to eliminate ambiguities encountered with a single MS/MS approach. The complex fragmentation behavior of these compounds of well-established structure is described which could be useful for structural characterization of unknown substances related to polymyxin B and E in the future.
Govaerts
Cindy
C
Laboratorium voor Farmaceutische Chemie en Analyse van Geneesmiddelen, Katholieke Universiteit Leuven, Faculteit Farmaceutische Wetenschappen, E. Van Evenstraat 4, B-3000 Leuven, Belgium.
Rozenski
Jef
J
Orwa
Jennifer
J
Roets
Eugène
E
Van Schepdael
Ann
A
Hoogmartens
Jos
J
D000900:Anti-Bacterial Agents / Q000737:chemistry*; D003091:Colistin / Q000737:chemistry*; D015394:Molecular Structure; D011113:Polymyxins / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
D000900:Anti-Bacterial Agents; D011113:Polymyxins; D003091:Colistin