Fig. 1
From: Structure of a VHH isolated from a naïve phage display library
Purification and characterization of VHH R419. a SDS-PAGE of VHH R419 purification using immobilized metal affinity chromatography. The three lanes (i–iii) correspond to imidazole concentrations of the elutions (0.25 M, 0.5 M and 1 M). b Analytical size exclusion chromatography of VHH R419 (dashed line) and VHH R326 (solid line). Despite having the same molecular weight (14.7 kDa), the proteins display different elution volumes. c Thermal stability (Tm = 66 °C) of R419 measured by CD spectroscopy. d Reversible refolding of R419 measured by CD spectroscopy. Samples were cooled back to 25 ºC immediately following thermal denaturation. e Aggregation propensity of R419 during refolding was measured by size exclusion chromatography (SEC). Unheated R419 was injected onto a analytical SEC column. R419 was heated, cooled to allow refolding, centrifuged to remove aggregates and injected onto a SEC column. The difference of the areas under the curves represents the amount of sample unfolded and lost due to aggregation