Ian Webb, Ph.D.

Research in the group focuses on developing advanced ion mobility/mass spectrometry tools for applications in structural and complex mixture analysis. We utilize site-specific gas-phase covalent modifications performed inside the mass spectrometer. Specifically, our group develops approaches using reactions of oppositely charged ions. Ion/ion reactions have many advantages, including speed (orders of magnitude faster than in bulk solvent), facile control over the extent of reaction, the ability to purify products by m/z, and the ability to quickly compare modified versus unmodified forms.

Research areas in the group include the following:

• Developing ion/ion reactions coupled to ion mobility/mass spectrometry for three-dimensional structural determination of proteins and protein complexes. These covalent modifications can give information on protein folding and connectivity. Ion mobility/mass spectrometry gives information about the overall size/shape, stoichiometry, intact mass, and primary sequence.

• Covalent derivatization of targeted functional groups as mobility modifiers by gas-phase ion/ion reactions. We exploit these ion/ion reactions in complex mixture analysis to enhance separation characteristics, adding additional orthogonality to mass spectrometry.

• Applications: Applying these methods to important biochemical, environmental, and other complex mixtures to facilitate rapid analyses with limited sample preparation. Also, we apply these methods to enable structural determination of proteins not amenable to traditional biophysical techniques. We also study the relationship between structure and function, especially for active site or allosteric binding of ligands, cofactors, and inhibitors.