Tandem Mass Spectrometry of Ribonuclease A and B: N-Linked Glycosylation Site Analysis of Whole Protein Ions
2001; American Chemical Society; Volume: 74; Issue: 3 Linguagem: Inglês
10.1021/ac015618l
ISSN1520-6882
AutoresGavin E. Reid, James L. Stephenson, Scott A. McLuckey,
Tópico(s)Analytical Chemistry and Chromatography
ResumoRecently, an approach for the “top down” sequence analysis of whole protein ions has been developed, employing electrospray ionization, collision-induced dissociation, and ion/ion proton-transfer reactions in a quadrupole ion trap mass spectrometer. This approach has now been extended to an analysis of the [M + 12H]12+ to [M + 5H]5+ ions of ribonuclease A and its N-linked glycosylated analogue, ribonuclease B, to determine the influence of the posttranslational modification on protein fragmentation. In agreement with previous studies on the fragmentation of a range of protein ions, facile gas-phase fragmentation was observed to occur along the protein backbone at the C-terminal of aspartic acid residues, and at the N-terminal of proline, depending on the precursor ion charge state. Interestingly, no evidence was found for gas-phase deglycosylation of the N-linked sugar in ribonuclease B, presumably due to effective competition from the facile amide bond cleavage channels that “protect” the N-linked glycosidic bond from cleavage. Thus, localization of the posttranslational modification site may be determined by analysis of the “protein fragment ion mass fingerprint”.
Referência(s)