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https://hdl.handle.net/2440/71019
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Type: | Journal article |
Title: | Diagnostic di- and triphosphate cyclisation in the negative ion electrospray mass spectra of phosphoSer peptides |
Author: | Wang, T. Tran, T. Scanlon, D. Andreazza, H. Abell, A. Bowie, J. |
Citation: | Rapid Communications in Mass Spectrometry, 2011; 25(18):2649-2656 |
Publisher: | John Wiley & Sons Ltd |
Issue Date: | 2011 |
ISSN: | 0951-4198 1097-0231 |
Statement of Responsibility: | Tianfang Wang, T. T. Nha Tran, Denis Scanlon, Hayley J. Andreazza, Andrew D. Abell and John H. Bowie |
Abstract: | It has been shown previously that [M-H](-) anions of small peptides containing two phosphate residues undergo cyclisation of the phosphate groups, following collision-induced dissociation (CID), to form a characteristic singly charged anion A (H3P2O7(-), m/z 177). In the present study it is shown that the precursor anions derived from the diphosphopeptides of caerin 1.1 [GLLSVLGSVAKHVLPHVVPVIAEHL(NH2)] and frenatin 3 [GLMSVLGHAVGNVLGGLFKPKS(OH)] also form the characteristic product anion A (m/z 177). Both of the precursor peptides show random structures in water, but partial helices in membrane-mimicking solvents [e.g. in d3-trifluoroethanol/water (1:1)]. In both cases the diphosphopeptide precursor anions must have flexible conformations in order to allow approach of the phosphate groups with consequent formation of A: for example, the two pSer groups of 4,22-diphosphofrenatin 3 are seventeen residues apart. Finally, CID tandem mass spectrometric (MS/MS) data from the [M-H](-) anion of the model triphosphoSer-containing peptide GpSGLGpSGLGpSGL(OH) show the presence of both product anions A (m/z 177) and D (m/z 257, H4P3O10(-)). Ab initio calculations at the HF/6-31+G(d)//AM1 level of theory suggest that cyclisation of the three phosphate groups occurs by a stepwise cascade mechanism in an energetically favourable reaction (ΔG = -245 kJ mol(-1)) with a maximum barrier of +123 kJ mol(-1). |
Keywords: | Polyphosphates Diphosphates Phosphopeptides Spectrometry, Mass, Electrospray Ionization Molecular Conformation |
Rights: | Copyright © 2011 John Wiley & Sons, Ltd. |
DOI: | 10.1002/rcm.5171 |
Grant ID: | ARC |
Published version: | http://dx.doi.org/10.1002/rcm.5171 |
Appears in Collections: | Aurora harvest 5 IPAS publications |
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