Fig. 3: Biochemical analyses of ssDNA-mediated structural changes.

Circular Dichroism (CD) experiments for FL DriD and DriD(78-327). A 0.5 μM of DriD(78-327) and (B) 0.5 μM of FL DriD were used, and 2 μM and 5 μM of the 7-mer ssDNA were titrated into the apo protein, and CD spectra for protein plus each concentration of ssDNA were obtained. Wavelength in nm is plotted on the x axis, and mean residue ellipticity calculated as ((CD signal - corresponding blank signal) * 100) / (protein concentration in mM * path length in cm * number of residues in a monomer) is plotted on the y axis. Data points with dynode voltage >500 V are excluded. C Chymotrypsin proteolysis on DriD(78-327) in the presence and absence of ssDNA. Peptide fragments are color-coded by domain using the same color scheme in Fig. 1A. The Y105 cleavage site is highlighted in green. D Gel quantification for the DriD(78-327) proteolysis experiment is shown. E Chymotrypsin proteolysis of FL DriD in the presence and absence of ssDNA. F Gel quantification for the FL DriD proteolysis experiment is shown. For gel quantification, intensity was obtained by selecting bands in ImageJ, and then % FL DriD remaining was calculated by dividing the band intensity of DriD for each time point by the band intensity for DriD in the corresponding control lane, then multiplying by 100. Two independent experiments are plotted for DriD(78-327) and FL DriD proteolysis experiments with GraphPad, and the bar represents the median. All data points are shown.