HDX/MS

Hydrogen exchange with mass spectrometry (HX/MS) measures the rate of exchange of labile hydrogen atoms with deuterium in a protein’s backbone amide groups to report on structural changes in protein ensembles but at the peptide level, not individual amino acids. With the advent of integrated robotics for automated sample preparation and accurate protein structure prediction methods for improved data interpretation, HX/MS is an increasingly powerful method for probing solution-state protein ensembles. However, the technique is not used to its full potential due to its peptide resolution.

To address this problem, we developed PIGEON-FEATHER (Peptide ID Generation for Exchange Of Nuclei-Free Energy Assignment Through Hydrogen Exchange Rates): an HX/MS analysis method to calculate the absolute free energy of opening (∆Gop) for almost all the amino acids in a protein ensemble.