Figure 3. CBD-induced nanobody dimerization.
(a) BLI sensorgrams of DB-21 and DB-18 immobilized on streptavidin biosensors binding to CA-14 preequilibrated with different concentrations of CBD. (b) SEC analysis of CBD-induced heterodimerization. I) 5 μM (each) DB-21 and CA-14 and II) 10 μM (each) DB-18 and CA-14, in the presence or absence of CBD, were crosslinked by 50 μM bis-N-succinimidyl-(pentaethylene glycol) ester for 30 min at room temperature before SEC. III) 30 μM non-crosslinked DB-21, DB18, and CA-14 were separately analyzed. Elution volumes of protein standards are marked by triangles. Chromatograms in different groups are shown with different Y scales. (c) Measured KDs of the ternary complex formation. N.D., not detectable or too weak to be determined.