Fig. 4.

Spectroscopic properties of forked DNA constructs as a function of position relative to the ssDNA–dsDNA junction. (A) Fluorescence intensity changes at 370 nm for constructs containing single 2-AP probes. (B) Fluorescence intensity changes at 370 nm for constructs containing 2-AP dimer probes. (C) Ellipticity changes at 320 nm for constructs containing single 2-AP probes. (D) Ellipticity changes at 330 nm for constructs containing 2-AP dimer probes. Intensities for probes in ssDNA or dsDNA are at the left and right of each panel, respectively. Ellipticity changes are per mol 2-AP. Fluorescence intensity changes have been normalized to the intensity of the probe signal in the control ssDNA. The bars corresponding to the single 2-AP probes are centered on the probe position. The bars corresponding to the 2-AP dimer probes are broader and bracket the 2 positions involved.