FIGURE 1.

FVIII peptides 2076–2094 and 2149–2162, but not 2076–2090, exhibit reduced HD exchange in the presence of antibody KM33. A, the mass over charge ratio of the FVIII peptic peptides covering residues 2076–2094 and 2149–2162 that were dissolved in H₂O in the absence of KM33 (black spectra, top panel), in D₂O (cyan spectra, center panel), or in D₂O in the presence of KM33 (red spectra, bottom panel). B, the relative level of deuterium incorporation (Da) of FVIII peptides 2076–2090, 2076–2094, and 2149–2162 as a function of the incubation time in D₂O in the presence (red lines and circles) or absence (cyan lines and squares) of KM33. C, the obtained peptic peptides mapped onto the crystal structure of FVIII (PDB code 2R7E). Gray areas are uncovered by the peptide map. The deuterium incorporation level upon KM33 binding was identified to be unchanged for cyan areas and reduced for red areas. The inset zooms in on the FVIII C1 domain.