Despite a large amount of research on mass spectrometry of peptides and proteins, many fragmentation patterns are not fully understood. Computational methods, that are largely developed to help interpretation of different spectroscopies, are less able to provide MS/MS spectra independently on experiments up to now. QM+MM chemical dynamics simulations modeling ion-projectile collisions can provide in principle fragments due to collisions, from which theoretical MS/MS spectra can be obtained without prior experimental information. We have recently used this approach to understand MS/MS experiments of organic and biological molecules [1-4]. In this communication, we present in particular our advances in understanding and modeling MS/MS of polypeptides: from di- to octa-glycines. We have obtained the typical fragmentation pathways observed experimentally and we are able to understand fragmentation mechanisms. Thus, we can explain the different peaks observed experimentally and the corresponding mechanisms, e.g the formation of different cyclic structure products for both ions and neutrals as suggested experimentally [5]. Chemical dynamics simulations show that it is possible to obtain theoretical mass spectrometry spectra in good agreement with experiments. This is the first step towards a computational tool able to provide theoretical MS/MS useful for analytic purposes. References [1] R.Spezia, J.-Y.Salpin, M.-P.Gaigeot, W.L.Hase and K.Song. J. Phys. Chem. A 113, 13853–13862 (2009). [2] R.Spezia, A.Cimas, M.-P.Gaigeot, J.-Y.Salpin, K.Song and W.L.Hase. Phys. Chem. Chem. Phys. 14, 11724 – 11736 (2012). [3] D.Ortiz, P.Martin-Gago, A.Riera, K.Song, J.-Y.Salpin and R.Spezia. Int. J. Mass Spectrom. 335, 33-44 (2013). [4] D.Ortiz, J.-Y.Salpin, K.Song and R.Spezia. Int. J. Mass Spectrom. 358, 25-35 (2014). [5] R.Spezia, J.Martens, J.Oomens and K.Song. In preparation.

Toward theoretical mass spectrometry: from organic molecules to polypeptides

249th National Meeting (2015)

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