Effects of Abasic Sites on Triple Helix Formation Characterized by Affinity Cleaving
Technical rept. no. 3, 31 May 90-1 Jun 91,
CALIFORNIA INST OF TECH PASADENA DIV OF CHEMISTRY AND CHEMICAL ENGINEERING
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The stability of triple helical complexes between oligodeoxyribonucleotides containing one or two abasic 1,2-dideoxy-D-ribose residues bound to single 15-17 base pair sites within short duplex 30mer or plasmid DNA 4.9 kbp was examined by affinity cleaving. The triplets are significantly less stable than triplexes having the matched counterparts, T AT, CGC and G TA. Oligodeoxyribonucleotide-directed triple-helix formation offers a chemical approach for the sequence-specific binding of double-helical DNA that is 10 to the 6th power times more specific than restriction enzymes. Because triple-helix formation by pyrimidine oligodeoxyribonucleotides is limited to mostly purine tracts T AT, CGC triplets, it is desirable to find a general solution whereby oligodeoxyribonucleotides or other analogs could be used to bind all four base pairs of intact duplex DNA.
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