Figure 4.

Binding modes and UPLC-SEC chromatograms of TcdA-A2-V_HH complexes. (A) Binding modes for the interaction of TcdA-A2 and heterodimeric V_HHs in solution were determined based on molecular mass (M_obs), retention time (T_r) and TcdA neutralization data. (B) Chromatograms are shown for TcdA-A2 (red lines), the various antibodies (blue lines) and the 1:1 molar mixture of the two proteins (green lines). The M_obss of the peak in each chromatogram was estimated from MALS UV. Schematic representations of TcdA-A2, V_HH or V_HH-V_HH and complexes of the two proteins are shown for each peak. AU, absorbance unit.