Figure 3. Size-exclusion chromatography and SPR analyses of wild-type and mutant VLs. (A) Superdex 75™ size-exclusion chromatograms of VLs with monomeric peaks marked with arrowheads. For HVLP364S, the dimeric VL peak situated to the left of the monomeric peak is visible. (B) SPR analysis of VL binding to a Ni2+-NTA sensorchip. A llama VHH Monomer (A4.249) and a VH Dimer81 were used as controls. Measurements were taken at two dissociation phase windows (315–375 s and 780–840 s) and the mean values obtained from two independent trials performed in duplicates were recorded in the table. SPR experiments were performed with SEC-purified VLs.