Fig 4.

Analysis of the isotopic envelopes after gas-phase HDX-MS for selected signals of species bearing the same charge per monomer, namely MON²⁺, DIM⁴⁺ and TRI⁶⁺ (2164–2185 m/z range) of WT Aβ 1–40 (A) and SCR Aβ 1–40 (B). Left panels—isotopic envelopes corresponding to MON²⁺ (upper panels), DIM⁴⁺ (middle panels), TRI⁶⁺ (lower panels), for make-up gas flow 50 mL/min in the presence of ND₃/D₂O reagent. Right panels—decomposition of the experimental isotopic envelope into a family of isotopic envelopes of FWHM, expected for a single conformational state. The spectra were recalculated from m/z domain, (shown in left panels) to the domain of molecular mass of a monomeric unit in an oligomer (shown in right panels). Results of replicates of this experiments are shown in Figure C in S1 Appendix.