FIG. 9.
Binding affinity of wild-type OBD and N260 for ssDNA. (A) Binding isotherms obtained with ssDNA probes either containing (filled symbols) or lacking (open symbols) a 5′-GAGGC-3′ sequence and with the indicated protein. (B and C) Binding isotherms generated from the binding of the OBD to ssDNA probes of the indicated length (in nucleotides [nt]) at pH 7.4 (B) or pH 6.8 (C). (D) Apparent Ki values for single-stranded and double-stranded nonspecific DNA competitors of the indicated lengths against the OBD and N260 proteins. Ki and standard deviations were calculated from the IC50 of each competitor DNA obtained in triplicate with assays performed with 250 nM of protein and 15 nM of one TBS probe.