title: Comparing equilibrium and kinetic protein unfolding using time-resolved electrospray-coupled ion mobility mass spectrometry.
abstract: Protein unfolding intermediates are thought to play a critical role in conformational pathogenesis, acting as a 'gateway' to inactivation or pathogenic aggregation. Unfolding intermediates have long been studied either by populating partially-folded species at equilibrium using incresingly denaturing conditions, or by transiently populating 'kinetic' intermediates under fully denaturing conditions using a time-resolved approach (e.g. stopped-flow fluorescence). However, it is not clear that the folding intermediates populated under equilibrium conditions are comparable to intermediates transiently populated in kinetic experiments. In this work, we combine time-resolved electrospray (TRESI) with travelling wave Ion Mobility Spectrometry (IMS) for the first time to directly compare equilibrium and kinetic unfolding intermediates of cytochrome c. Our results show a high degree of correlation between all species populated under these substantially different regimes.
authors.affiliation: Department of Chemistry and Centre for Research in Mass Spectrometry, York University, Toronto, ON, Canada. dkwilson@yorku.ca.
authors.forename: Peter
authors.initials: P
authors.lastname: Liuni
authors.forename: Bin
authors.initials: B
authors.lastname: Deng
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Wilson
mesh_terms: D045304:Cytochromes c / Q000737:chemistry; D007700:Kinetics; D058767:Protein Unfolding; D011506:Proteins / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D011506:Proteins; D045304:Cytochromes c