Journal article
Highly Charged Protein Ions: The Strongest Organic Acids to Date
MA Zenaidee, MG Leeming, F Zhang, TT Funston, WA Donald
Angewandte Chemie International Edition | WILEY-V C H VERLAG GMBH | Published : 2017
Abstract
The basicity of highly protonated cytochrome c (cyt c) and myoglobin (myo) ions were investigated using tandem mass spectrometry, ion–molecule reactions (IMRs), and theoretical calculations as a function of charge state. Surprisingly, highly charged protein ions (HCPI) can readily protonate non-polar molecules and inert gases, including Ar, O2, and N2 in thermal IMRs. The most HCPIs that can be observed are over 130 kJ mol−1 less basic than the least basic neutral organic molecules known (tetrafluoromethane and methane). Based on theoretical calculations, it is predicted that protonated cyt c and myo ions should spontaneously lose a proton to vacuum for charge states in which every third res..
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Awarded by Australian Research Council
Funding Acknowledgements
We thank the Australian Research Council for funding this research (DP160102681). We would like to thank Dr. Kelvin Lee, Mr. Alireza Kharazmi, and Prof. Scott Kable (UNSW Sydney) for contributing to the instrumentation for ion-molecule reaction experiments. We thank Profs. Richard O'Hair, Evan Bieske (University of Melbourne), and Stephen Blanksby (Queensland University of Technology) for helpful discussions.