Figure 2: Deuterium exchange of E-protein in unexpanded DENV2 and DENV1 at 28 °C in solution.

(a) Representative mass spectra of peptides from E-protein of DENV2 and DENV1 for undeuterated and t=1 min of deuterium exchange at 28 °C. Differences in sequence between DENV2 and DENV1 are indicated in black. Dashed line represents centroid of the mass envelope. Average number of deuterons exchanged in each peptide is determined by subtracting the centroid of the deuterium exchanged peptide from the undeuterated peptide. Relative deuterium exchange (RFU) is the fraction of average deuterons exchanged relative to the maximum number of exchangeable amides in each peptide. (b,c) RFU values for each E-protein pepsin fragmentation peptide listed from the N-to-C-terminus after 1 min of deuterium exchange are shown for DENV2 and DENV1 at 28 °C in a modified mirror plot respectively. Each dot represents one pepsin fragment peptide, Y-axis-Relative fractional uptake of deuterium (RFU), X-axis-pepsin fragment peptides, listed from N to C terminus. (d) RFU after 1 min of deuterium exchange at 28 °C is mapped onto whole viral particles in a colour coded gradient scale on DENV2 (PDB ID: 1OAN) and DENV1 (PDB ID: 4CCT). Regions with no peptide coverage are white. Each E-protein monomer is outlined (consisting of 6 monomers). E-protein units adjacent to the five-fold, two-fold and three-fold vertices are labelled A, B and C respectively. Insets: RFU after 1 min of deuterium exchange at 28 °C mapped onto a unit of E-protein dimer from DENV2 and DENV1. S.e. for each peptide is shown as shaded regions along the X-axis. The s.e. for a given peptide represents a single sigma s.d.. of all (minimum three) the independent HDXMS measurements.