Figure 2.

(a) Fluorescence emission spectra for E89-23 at various ligase concentrations. A fixed excitation wavelength (320 nm) is used throughout. Emission spectra for DNA-free buffer solutions containing equal amounts of ligase are taken as background and subtracted from the measured fluorescence spectra. (b) Excitation spectra of E89-23 at various ligase concentrations. Fluorescence emission is collected at a fixed wavelength of 370 nm, and buffer solutions containing equal amounts of DNA is taken as the background and subtracted from the measured spectra.