Fig. 6: Bpa residues H131, F138, and R145 are involved in HspR recruitment to Bpa-mediated proteasomal degradation.

A In vitro degradation assays of wild-type HspR using site-directed variants of Bpa, followed by Coomassie-stained SDS-PAGE. B Progress of degradation was measured by following the change in the HspR gel band intensity shown in A. Densitometric analysis was conducted from gel triplicates and data are presented as mean ± standard deviation in gel band intensity. C Binding of wild-type HspR to fluorescently labeled Bpa variants was measured by recording the temperature-related fluorescence intensity changes at different concentrations of substrate. Reactions were run in triplicates and dependency of bound Bpa fraction on the substrate concentration was fitted with the solution to the quadratic equation for the fraction of fluorescent molecules that formed the complex. Data are presented as mean ± standard deviation.