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Infrared Spectroscopy of Fragments from Doubly Protonated Tryptic Peptides |
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| Authors: | Benjamin J Bythell Dr Undine Erlekam Dr Béla Paizs Dr Philippe Maître Dr |
| Institution: | 1. Department of Molecular Biophysics, German Cancer Research Center, Im Neuenheimer Feld 580, Heidelberg (Germany), Fax: (+49)?6221‐422333;2. Laboratoire de Chimie Physique, Université Paris‐Sud 11, Faculté des Sciences, UMR8000 CNRS, Bat. 350, 91405 Orsay Cedex (France), Fax: (+33)?169‐1561188 |
| Abstract: | Most proteins in proteomics are identified from tandem mass spectra of doubly protonated tryptic peptides. Statistical studies indicate that these spectra fall into two distinct classes. IR spectroscopy experiments and DFT calculations performed on model b2 ions show that peptides producing Class I spectra form protonated oxazolone ions (see figure) and not protonated diketopiperazines as proposed elsewhere.  |
| Keywords: | density functional calculations fragmentation pathway mass spectrometry peptides vibrational spectroscopy |