Figure 3.

ssDNA binding properties of RPA^f. (A) Excitation and emission spectra of RPA^f show maximum values at 555 nm (λ_ex) and 566 nm (λ_em). (B) RPA^f was excited at 535 nm and emission spectra were recorded in the absence or presence of ssDNA [(dT)₉₇] orplasmid dsDNA. A ∼5% increase in fluorescence signal is observed when ssDNA is present in the reaction. (C) Electromobility band shift analysis (EMSA) of RPA^WT (top) and RPA^f (bottom) binding to 50 nM ³²P-labeled (dT)₃₅ oligonucleotides show bound and unbound complexes and (D) quantitation of the EMSA data show stoichiometric binding to ssDNA for both RPA and RPA^f.