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. 2003 Apr 15;31(8):2178–2186. doi: 10.1093/nar/gkg308

Figure 4.

Figure 4

(a) Single molecule fluorescence scanning confocal image (7.5 × 10.0 µm) of CT ds DNA labeled with H-258 (40 µM) at a [H-258]/[DNA bp] ratio of 0.2 in 50 mM phosphate buffer, pH 7.0. DNA molecules bind to the amino-modified glass cover slide due to electrostatic interactions. Imaging was performed at room temperature with a resolution of 50 nm/pixel, λexc = 360 nm, average excitation power ∼1 kW/cm2 and 6 ms integration time per pixel (intensity: 0–50 counts/6 ms). (b) Fluorescence intensity and lifetime transient of a H-258 labeled DNA molecule ([H-258]/[DNA bp] = 0.2) with a time resolution of 100 ms. The transients demonstrate that weaker bound H-258 molecules show shorter fluorescence lifetimes and lower photostability.