In vitro crosslinking of DNA by 8-methoxypsoralen visualized by electron microscopy.
By electron microscopic visualisation of totally denatured DNA, we have detected photochemically induced 8-methoxypsoralen crosslinks in vitro after irradiation at 360 nm. The amount of crosslinks was expressed as the percentage of DNA length which was kept in double-stranded appearance by closely situated crosslinks. This percentage correlated well with irradiation time, irradiation intensity, and the concentration of 8-methoxypsoralen. These parameters have also been correlated with the mean size and the size distribution of non-crosslinked regions of DNA, so called bubbles. For a comparison with another psoralen type, we have carried out a similar set of experiments using 4,5,8-trimethylpsoralen.
D003374:Coumarins; D004247:DNA; D004307:Dose-Response Relationship, Radiation; D008730:Methoxsalen; D008854:Microscopy, Electron; D009691:Nucleic Acid Denaturation; D010777:Photochemistry; D014307:Trioxsalen; D014466:Ultraviolet Rays
D003374:Coumarins; D004247:DNA; D008730:Methoxsalen; D014307:Trioxsalen