Figure 5

Par17 binds to double-stranded DNA. A. Binding of Par17 and Par14 to DNA. Radiolabeled Par17-QR and Par14 proteins were used for DNA cellulose binding assays. Following incubation of dsDNA with protein lysates, bound protein was eluted with increasing KCl concentrations. 20% of lysate (Lys) and KCl fractions were analyzed by SDS-PAGE and autoradiography. Asterisk (*), unspecific band caused by free label. Prominent signals for both, Par17 and Par14, are seen at 100 and 200 mM KCl. Porin was used as negative control and was washed off at 0 and 50 mM KCl. B. Quantitative analysis. Par17-QR, -RS and Par14 fused to EGFP as well as EGFP without fusions were subjected to the DNA binding assay. Blots were quantitatively analyzed by densitometry. Data from each experiment were normalized to their sum. Standard deviations are given from duplicate experiments. Par17 and Par14 proteins were eluted from dsDNA cellulose at 100, 200 and to a lesser extent at 500 mM KCl pointing to similar DNA-binding of the two parvulin proteins at physiological salt concentrations. EGFP without fusions was completely eluted from DNA cellulose at 50 mM KCl.