HDX-MS

Proteins (~ 5 µl at 0.5-10 µM) are diluted 20 times in a deuterated buffer (at physiological pH) before a rapid quench at 4°C and pH 2.6.The quenched solution is then digested online (pepsin column) and peptides are desalted on a C18 cartridge before being separated on a C18 column at 4°C. The whole sample preparation, digestion and MS analysis is automated thanks to our Automated HDX robot (LeapTec) coupled to the Synapt G2-Si (Waters) (Figure 1). The data analysis is also entirely automated (Figure 2). Figure 1. Automated HDX-MS solution including the sample preparation robot (LeapTec), the M-Class Acquity UPLC, the HDX-module for protein digestion and peptide separation at 4°C and the SynaptG2Si (Waters). Figure 2. Dynamix (Waters) software automatically generates sequence coverage maps (A), extracts the mass increment of each peptide at each timepoint (B) to draw deuteration curve (C). Heatmaps are then generated (D) and can be imported to Pymol, if a structure of the protein of interest is available (E).