Fig. 3

Effects of chemical stress on VLP stability. a 6His-VLPs (upper row) and ΔHis-VLPs (lower row) were stressed by chaotropic agent (urea) in the absence or presence (+DTT) of 100 mM DTT and subsequently analyzed on PageBlue-stained 2.6% native agarose gels. Corresponding samples were analyzed by dot blots using mAb3120 antibody specific for assembled VLPs, which is shown below the agarose gel pictures. Bar diagrams show the normalized densitometric analysis of stained protein bands, separated by NAGE. 6His-VLPs (6) are indicated in black (T = 4) and grey (T = 3), ΔHis-VLPs (Δ) in orange (T = 4) and blue (T = 3) bars. Four independent purifications of 6His-VLPs and three independent purifications of ΔHis-VLPs were analyzed and 4–10 stained NAGEs per test were quantified. Untreated reference samples used for normalization are marked with *. Average values are shown and standard deviations are indicated by error bars. Only experimental conditions which resulted in RSI (relative signal intensity) values above zero are specified. b 6His-VLPs (upper row) and ΔHis-VLPs (lower row) were stressed by detergent (SDS) and analyzed as in a. c 6His-VLPs (upper row) and ΔHis-VLPs (lower row) were stressed by different pH and analyzed as in a