Noncovalent Interactions Studied by Temperature-Programmed Native ESI-MS
Professor, Department of Chemistry and Applied Sciences
Friday, June 21, 2019
C2-361 (Reading Room)
Abstract: Using so-called "native" spray conditions, electrospray ionization (ESI) allow the observation of noncovalently bound complexes in the gas phase, and to determine noncovalent biomolecular binding affinities using mass spectrometric read-out. This has great advantages over other biophysical methods such as SPR or CD, because details of different ligation states and the stoichiometry and influence of cofactors can be clearly discerned using MS. Here we present the development of a temperature controlled ESI source for T-dependent binding assays. This gives access to the full thermodynamic information, i.e., enthalpic (∆H) and entropic (∆S) contributions to the Gibbs free energy (∆G) for noncovalent binding interactions measured by ESI-MS, in a stoichiometry-specific manner. We also have developed a T jump source, where we can follow dissociation, melting, and unfolding / refolding kinetics of biomolecular assemblies. The technology is being applied successsfully to DNA duplexes, triple helices, and DNA G quadruplexes, and other complex noncovalent assemblies such as collagen model peptides that form triple helices.
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