Disulfide bonds are post translational modifications playing essential roles in the biological activity and stability of numerous peptides and proteins. Intra-molecular disulfide bonds are found in various natural-occurring peptides such as animal venoms. In such peptides, the appropriate cysteine connectivity provides the required conformation for efficient binding to their molecular targets, which ensures their bioactivity.<br/>The characterization of cysteine connectivities of such peptides of pharmaceutic interest was performed using ion mobility mass spectrometry (IMMS) and capillary zone electrophoresis mass spectrometry (CZEMS). Both IMMS and CZEMS could discriminate connectivities after parameters optimization. Nonetheless significant differences in migration order between the gas phase and the aqueous phase were observed.<br/>We attempted to explain the difference in migration behavior between gas phase and in solution using theoretical calculations based on molecular mechanics. Charge distributions, structural effects, and shape factors were investigated to explain the experimental results.

Combination of capillary electrophoresis and ion mobility coupled to mass spectrometry to theoretical calculations for cysteine connectivity identification in peptides bearing two intra-molecular disulfide bonds

2019 Spring National Meeting

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