Figure 1:
Effects of biotinylation on RPA-ssDNA binding. Lanes: 1, free ssDNA; 2-6, ssDNA bound by RPA pre- or posttreated with 0, 50, 100, 200, and 400 μM NHS-biotin. Panel A: Addition of increasing amounts of NHS-biotin prior to addition of ssDNA blocked critical lysine residues for ssDNA interaction and thus abolished binding affinity. Panel B: Addition of ssDNA prior to NHS-biotin, however, shielded critical lysine residues from modification and showed little effect of biotin on the formed RPA-ssDNA complex.