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PhD Lisanne Kempkes: revealing the molecular structures of product ions

Date of news: 31 March 2019

On March 19, PhD student Lisanne Kempkes successfully defended her doctoral thesis, entitled: "Reaction Mechanisms of Collision and Electron Induced Peptide Dissociation Revealed by Ion Spectroscopy.”  Prof. dr. J. Oomens acted as promotor, Dr. J.K. Martens as co-promotor.

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Kempes' research
To study the biological function of a protein, knowing the sequence of the hundreds of amino acids it contains is essential. Mass spectrometry is widely used in proteomics to identify this amino acid sequence. This typically involves cleaving the proteins into smaller fragments. Next, the produced fragment ion masses are processed using computational algorithms and compared to databases known from DNA sequences and established dissociation patterns.

Kempkes investigated the reaction mechanisms behind collision- and electron induced dissociation. These are common methods, but not fully understood. Especially electron induced dissociation produces complex mass spectra and the radical-driven dissociation mechanisms remain elusive. The general aim of Kempkes' research was to obtain a better understanding of the chemical reactions at the level of the actual molecular structures, that take place during protein fragmentation inside mass spectrometers. Therefore she used infrared ion spectroscopy combined with quantum-chemical calculations.

By revealing the molecular structures of product ions, sequencing algorithms can be eventually improved. In this way, proteins are more accurately identified and specific protein modifications in diseases can be better understood.

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Kempkes enjoyed working at FELIX not only because of her own research, but also because of the collaborations with visiting researchers from all over the world. Furthermore she enjoyed to share her work internally, for example at the biannual FELIX user meeting, as well as externally at international conferences. She is proud that her time at FELIX was successful and led to a PhD thesis containing 7 published articles, and even more to come.

More information
Hard copies of the PhD thesis are available. Please contact Lisanne Kempkes: L.Kempkes@science.ru.nl