Hydrogen/Deuterium eXchange mass spectrometry (HDX-MS) can be used to study structural conformation of a protein or its interaction as a complex. The method is useful for studying any type of epitopes (Conformational or Linear). The protein (or complex) is submerged into D2O which will allow exposed Hydrogen atoms to exchange with Deuterium atoms. The epitope region on the antigen will display reduced exchange rate when complexed with the antibody. The differences in this exchange process can occur over seconds to hour timeframe and is an indicator of the local structure. The Deuterium is then frozen or "quenched" at low temperature and pH and the location of the Deuterium uptake can be detected accurately using high resolution mass spectrometry.
HDX has been utilized on a research scale for many years at the academic level and within larger pharmaceutical companies. More recently, with the advancement of automated robotics, sample handling and data analysis software, HDX can now be offered on a timescale and with sample consumptions reasonable for more mainstream analysis. CovalX is using the latest mass spectrometry equipment, HDX automation robotics and software to rapidly characterize the binding sites using HDXMS. Additionally, CovalX has technicians with combined decades of experience optimizing and understanding HDXMS workflows.
An overview of epitope mapping technologies can be seen here.