title: Cross-linking of double-helical nucleic acids with a photoreactive analogue of ethidium.
abstract: Intercalation of the ethidium analogue 3,5-diazido-5-ethyl-6-phenylphenanthridinium into double helices followed by irradiation with blue or ultraviolet light results in cross-linking between the two strands with an efficiency around 30% for DNA, RNA, and DNA-RNA hybrids. Details of this reaction and a convenient synthesis of the ethidium analogue are described. Stable tertiary structure in RNA impedes intercalation and thus reduces the efficiency of cross-linking. In contrast to the ethidium derivative, various acridine diazides show little or no cross-linking ability.
mesh_terms: D001386:Azides; D003432:Cross-Linking Reagents; D004247:DNA; D004996:Ethidium / Q000031:analogs & derivatives*; D006860:Hydrogen Bonding; D009696:Nucleic Acids; D010777:Photochemistry; D012335:RNA, Ribosomal; D012343:RNA, Transfer
chemical_list: D001386:Azides; D003432:Cross-Linking Reagents; D009696:Nucleic Acids; D012335:RNA, Ribosomal; D004247:DNA; D012343:RNA, Transfer; D004996:Ethidium