Article
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Evidence of Gas Phase Glucosyl Transfer and Glycation in the CID/HCD-Spectra of S-Glucosylated Peptides
Version 1
: Received: 5 June 2024 / Approved: 5 June 2024 / Online: 6 June 2024 (03:03:43 CEST)
A peer-reviewed article of this Preprint also exists.
Buchowiecka, A.K. Evidence of Gas Phase Glucosyl Transfer and Glycation in the CID/HCD-Spectra of S-Glucosylated Peptides. Int. J. Mol. Sci. 2024, 25, 7483. Buchowiecka, A.K. Evidence of Gas Phase Glucosyl Transfer and Glycation in the CID/HCD-Spectra of S-Glucosylated Peptides. Int. J. Mol. Sci. 2024, 25, 7483.
Abstract
. Protein cysteine S-glycosylation is a relatively rare and less well characterized post-translational modification (PTM). Creating reliable model proteins that carry this modification is challenging. The lack of available model or natural S-glycosylated proteins significantly hampers the development of MS-based methodologies for detecting protein cysteine S-glycosylation in real-world proteomic studies. There is also limited MS-sequencing data describing easier to create synthetic S-glycopeptides. Here, we present the results of an in-depth manual analysis of automatically annotated CID/HCD spectra for model S-glucopeptides. The CID spectra show a long series of y/b-fragment ions with retained S-glucosylation, regardless of the dominant m/z signals corresponding to neutral loss of 1,2-anhydroglucose from the precursor ions. In addition, the spectra show signals manifesting glucosyl transfer from the cysteine position onto Lys, Arg side chains, and a peptide N-terminus. Other spectral evidence indicates that the N-glucosylated initial products of transfer are converted into N-furanosylated (i.e., glycated) structures due to Amadori rearrangement. We discuss the peculiar transfer of the glucose oxocarbenium ion (Glc+) to positively charged guanidinium residue (ArgH+) and propose a mechanism for the gas-phase Amadori rearrangement involving a hydride ion shift.
Keywords
glycoproteomics; S-glycosylation; gas phase glycosyl transfer; glycation; Amadori rearrangement
Subject
Biology and Life Sciences, Biochemistry and Molecular Biology
Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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