by using published values for the association constant for ethidium binding to dna and evaluating the final superhelix density ( after removal of ethidium ) of the dna on gels , we calculated an unwinding angle of 29 degrees +/- 3 degrees . assuming an unwinding angle of 28 degrees for the noncovalent intercalation of psoralen derivatives , we used the same procedure to determine intercalation binding constants .
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evaluating
C0184661
procedure