Gas-phase intermolecular phosphate transfer within a phosphohistidine phosphopeptide dimer

•Fragmentation of phosphoramidate-containing peptides by CID in a QIT was assessed.•pHis homodimer formation facilitates intermolecular phosphate transfer during CID.•Dimer formation and phosphate transfer is dependent on a C-terminal basic Lys. The hydrogen bonds and electrostatic interactions that...

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Bibliographic Details
Published in:International journal of mass spectrometry 2014-06, Vol.367, p.28-34
Main Authors: Gonzalez-Sanchez, Maria-Belen, Lanucara, Francesco, Hardman, Gemma E., Eyers, Claire E.
Format: Article
Language:English
Subjects:
CID
Gas-phase dimer
Histidine phosphorylation
Non-covalent interactions
Phosphoramidate
Phosphotransfer
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Summary:•Fragmentation of phosphoramidate-containing peptides by CID in a QIT was assessed.•pHis homodimer formation facilitates intermolecular phosphate transfer during CID.•Dimer formation and phosphate transfer is dependent on a C-terminal basic Lys. The hydrogen bonds and electrostatic interactions that form between the protonated side chain of a basic residue and the negatively charged phosphate of a phosphopeptide can play crucial roles in governing their dissociation pathways under low-energy collision-induced dissociation (CID). Understanding how phosphoramidate (i.e. phosphohistidine, phospholysine and phosphoarginine), rather than phosphomonoester-containing peptides behave during CID is paramount in investigation of these problematic species by tandem mass spectrometry. To this end, a synthetic peptide containing either phosphohistidine (pHis) or phospholysine (pLys) was analyzed by ESI-MS using a Paul-type ion trap (AmaZon, Bruker) and by traveling wave ion mobility-mass spectrometry (Synapt G2-Si, Waters). Analysis of the products of low-energy CID demonstrated formation of a doubly ‘phosphorylated’ product ion arising from intermolecular gas-phase phosphate transfer within a phosphopeptide dimer. The results are explained by the formation of a homodimeric phosphohistidine (pHis) peptide non-covalent complex (NCX), likely stabilized by the electrostatic interaction between the pHis phosphate group and the protonated C-terminal lysine residue of the peptide. To the best of our knowledge this is the first report of intermolecular gas-phase phosphate transfer from one phosphopeptide to another, leading to a doubly phosphorylated peptide product ion.
ISSN:1387-3806
1873-2798
DOI:10.1016/j.ijms.2014.04.015