title: Site-directed psoralen crosslinking of DNA.
abstract: A technique has been developed for placing site-specific crosslinks into DNA by using a psoralen derivative containing a sulfhydryl group. Plasmid pBR322 was nicked at the unique BamHI restriction site, and mercurated pyrimidines were introduced by nick-translation. Then the psoralen was specifically directed to this site in the dark through a Hg-S linkage prior to irradiation to form a crosslink. The location of interstrand cross-links was examined by electron microscopy of Pst I-cut molecules and found to be at or near the BamHI site.
mesh_terms: D003432:Cross-Linking Reagents; D004247:DNA; D004262:DNA Restriction Enzymes; D011564:Furocoumarins; D008722:Methods; D008854:Microscopy, Electron; D009941:Organomercury Compounds; D013438:Sulfhydryl Compounds; D014307:Trioxsalen / Q000031:analogs & derivatives
chemical_list: D003432:Cross-Linking Reagents; D011564:Furocoumarins; D009941:Organomercury Compounds; D013438:Sulfhydryl Compounds; C035639:2-pyridyldithioethylmethylamidodiethoxyethane methylaminomethyltrimethylpsoralen; D004247:DNA; D004262:DNA Restriction Enzymes; D014307:Trioxsalen