| Title |
Structure characterization of unexpected covalent O-sulfonation and ion-pairing on an extremely hydrophilic peptide with CE-MS and FT-ICR-MS
|
|---|---|
| Published in |
Analytical & Bioanalytical Chemistry, June 2015
|
| DOI | 10.1007/s00216-015-8826-8 |
| Pubmed ID | |
| Authors |
Martin Pattky, Simone Nicolardi, Beatrix Santiago-Schübel, Daniel Sydes, Yuri E. M. van der Burgt, Antonia N. Klein, Nan Jiang, Jeannine Mohrlüder, Karen Hänel, Janine Kutzsche, S. A. Funke, D. Willbold, S. Willbold, C. Huhn |
| Abstract |
In this study, we characterized unexpected side-products in a commercially synthesized peptide with the sequence RPRTRLHTHRNR. This so-called peptide D3 was selected by mirror phage display against low molecular weight amyloid-β-peptide (Aβ) associated with Alzheimer's disease. Capillary electrophoresis (CE) was the method of choice for structure analysis because the extreme hydrophilicity of the peptide did not allow reversed-phase liquid chromatography (RPLC) and hydrophilic interaction stationary phases (HILIC). CE-MS analysis, applying a strongly acidic background electrolyte and different statically adsorbed capillary coatings, provided fast and efficient analysis and revealed that D3 unexpectedly showed strong ion-pairing with sulfuric acid. Moreover, covalent O-sulfonation at one or two threonine residues was identified as a result of a side reaction during peptide synthesis, and deamidation was found at either the asparagine residue or at the C-terminus. In total, more than 10 different species with different m/z values were observed. Tandem-MS analysis with collision induced dissociation (CID) using a CE-quadrupole-time-of-flight (QTOF) setup predominantly resulted in sulfate losses and did not yield any further characteristic fragment ions at high collision energies. Therefore, direct infusion Fourier transform ion cyclotron resonance (FT-ICR) MS was employed to identify the covalent modification and discriminate O-sulfonation from possible O-phosphorylation by using an accurate mass analysis. Electron transfer dissociation (ETD) was used for the identification of the threonine O-sulfation sites. In this work, it is shown that the combination of CE-MS and FT-ICR-MS with ETD fragmentation was essential for the full characterization of this extremely basic peptide with labile modifications. |
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Geographical breakdown
| Country | Count | As % |
|---|---|---|
| Unknown | 1 | 100% |
Demographic breakdown
| Type | Count | As % |
|---|---|---|
| Scientists | 1 | 100% |
Mendeley readers
The data shown below were compiled from readership statistics for 12 Mendeley readers of this research output. Click here to see the associated Mendeley record.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| Unknown | 12 | 100% |
Demographic breakdown
| Readers by professional status | Count | As % |
|---|---|---|
| Researcher | 4 | 33% |
| Student > Ph. D. Student | 2 | 17% |
| Student > Doctoral Student | 1 | 8% |
| Professor | 1 | 8% |
| Student > Master | 1 | 8% |
| Other | 1 | 8% |
| Unknown | 2 | 17% |
| Readers by discipline | Count | As % |
|---|---|---|
| Chemistry | 4 | 33% |
| Biochemistry, Genetics and Molecular Biology | 3 | 25% |
| Pharmacology, Toxicology and Pharmaceutical Science | 1 | 8% |
| Medicine and Dentistry | 1 | 8% |
| Business, Management and Accounting | 1 | 8% |
| Other | 0 | 0% |
| Unknown | 2 | 17% |
Attention Score in Context
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#22,759,802
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#7,542
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