DETECTION AND KINETIC-STUDIES OF TRIPLEX FORMATION BY OLIGODEOXYNUCLEOTIDES USING REAL-TIME BIOMOLECULAR INTERACTION ANALYSIS (BIA)

Real-time biomolecular interaction analysis (BIA) has been applied to tripler formation between oligodeoxynucleotides. 5'-Biotinylated oligo nucleotides were immobilised on the streptavidin-coated surface of a b iosensor chip and subsequently hybridised to their complementary stran d, Sequence-specific tripler formation was observed when a suitable th ird-strand oligopyrimidine was injected over the surface-bound duplex. In addition, a single-stranded oligonucleotide immobilised on the chi p surface was able to capture a DNA duplex by tripler recognition, The presence of spermine increases the rate of association between the th ird strand and immobilised duplex, but at elevated spermine concentrat ions non-specific association is observed, A preliminary kinetic analy sis of tripler formation at pH 5.2 by an 11 mer third strand containin g thymine, cytosine and uracil is reported, Values for the association and dissociation rate constants were determined to be (1.9 +/- 0.2) x 10(3) M(-1) S-1 and (8.1 +/- 1.9) x 10(-5) s(-1), respectively.