Premium
Structural characterization of sialylated glycoforms of H. influenzae by electrospray mass spectrometry: fragmentation of protonated and sodiated O ‐deacylated lipopolysaccharides
Author(s) -
Li Jianjun,
Dzieciatkowska Monika,
Hood Derek W.,
Cox Andrew D.,
Schweda Elke K. H.,
Moxon E. Richard,
Richards James C.
Publication year - 2007
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.2916
Subject(s) - chemistry , oligosaccharide , fragmentation (computing) , tandem mass spectrometry , protonation , mass spectrometry , lactose , carbohydrate conformation , chromatography , stereochemistry , biochemistry , ion , nuclear magnetic resonance spectroscopy , organic chemistry , computer science , operating system
Sialylated lipopolysaccharide (LPS) glycoforms from Haemophilus influenzae were characterized by tandem mass spectrometry using a new generation hyphenated mass spectrometer which combines a triple quadrupole and a linear ion trap (Q‐Trap). The fragmentation of both protonated and sodiated molecular ions from O‐deacylated LPS (LPS‐OH) obtained in MS 2 experiments in the positive mode was studied. The MS 2 spectra of protonated ions provided unambiguous evidence for the presence and sequence of sialylated lactosamine present in lacto‐N‐neotetraose oligosaccharide extensions but not for sialyl‐lactose structures whilst fragmentation of sodiated adducts, [M+Na] + , afforded information diagnostic of mono‐ and disialylated lactose extensions. To study this we used a highly sialylated LPS from a H . influenzae strain capable of sialyl‐lactose expression only. We then applied the method to the H . influenzae genome strain, Rd, in which glycoforms containing both sialyl‐lactose and sialyl‐lacto‐N‐neotetraose were detected from diagnostic B‐ions at m/z 638.2 ([Neu5Ac 1 Hex 2 +Na] + ) and 657.2 ([Neu5Ac 1 Hex 1 HexNAc 1 +H] + ). Unique fragmentation patterns provided the locations and sequences of these oligosaccharide extensions. This is the first time both sialylated lactose and sialylated lacto‐N‐neotetraose units have been detected and characterized by tandem mass spectrometry in the same molecule. This methodology is of general applicability for determination of common sialylated oligosaccharide extension in bacterial LPS. Copyright © 2007 John Wiley & Sons, Ltd. The copyright in the contributions of J. Li, M. Dzieciatkowska, A. D. Cox and J. C. Richards belongs to the Crown in the right of Canada and such copyright material is reproduced with the permission of the National Research Council of Canada.