(a) ESI mass spectrum acquired in negative ion mode for
aqueous
ammonium acetate solution (200 mM, pH 7 and 25 °C) of NoV VA387
P dimer (P2, 12 μM), GM3 trisaccharide (80 μM)
and Pref (4 μM). Another minor form of P dimer (P′2, MW 74,080 Da) was also detected with lower abundance. Inset,
normalized distribution of GM3 bound to P2 after correction
for nonspecific ligand binding. (b) ESI mass spectrum acquired in
negative ion mode for aqueous ammonium acetate solution (200 mM, pH
7 and 25 °C) of NoV VA115 P dimer (P2, 12 μM,
MW 67,712 Da), GM3 trisaccharide (80 μM), and Pref (4 μM). Inset, normalized distribution of GM3 bound to P2 after correction for nonspecific ligand binding.