Hoechst 33258--poly(dG-dC).poly(dG-dC) complexes of three types.
It was found recently that Hoechst 33258, a dsDNA fluorescent dye used in cytological studies, is an efficient inhibitor of the interaction of TATA-box-binding protein with DNA, DNA topoisomerase I, and DNA helicases. In addition it proved to be a radioprotector. Biological activity of Hoechst 33258 may be associated with dsDNA complexes of not only monomeric, but also dimeric type. In this work, the Hoechst 33258 interaction with poly(dG-dC).poly(dG-dC) was studied using UV-vis and fluorescent spectroscopy, circular and flow-type linear dichroism. It was found that Hoechst 33258 formed with poly(dG-dC).poly(dG-dC) complexes of three types, namely, monomeric, dimeric, and, apparently, tetrameric, and their spectral properties were studied. Complexes of monomeric and dimeric types competed with distamycin A, a minor groove ligand, for binding to poly(dG-dC).poly(dG-dC). We proposed that Hoechst 33258 both monomers and dimers form complexes of the external type with poly(dG-dC).poly(dG-dC) from the side of the minor groove.
Streltsov
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SA
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, Moscow 119991, Russia. strelcov@eimb.ru
Zhuze
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AL
D006690:Bisbenzimidazole / Q000378:metabolism*; D002942:Circular Dichroism; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D019281:Dimerization; D005456:Fluorescent Dyes / Q000378:metabolism*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011066:Poly C / Q000737:chemistry / Q000378:metabolism*; D011068:Poly G / Q000737:chemistry / Q000378:metabolism*; D011089:Polydeoxyribonucleotides; D011119:Polynucleotides / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
D005456:Fluorescent Dyes; D011089:Polydeoxyribonucleotides; D011119:Polynucleotides; D011068:Poly G; D011066:Poly C; D004264:DNA Topoisomerases, Type I; D006690:Bisbenzimidazole