[Interaction of short nucleotide derivatives with nucleic acids. IV. Modification of DNA by an alkylating tetranucleotide reagents in the presence of effectors in perfect and imperfect complexes]. / Vzaimodeistvie proizvodnykh korotkikh oligonukleotidov s nukleinovymi kislotami. IV. Modifikatsiia DNK alkiliruiushchim proizvodnym tetranucleotida v prisutstvii éffektorov v sostave pravil'nykh i nepravil'nykh kompleksov.

ABSTRACT

It was demonstrated that any mismatches in a complex formed by an ssDNA target and a tetranucleotide at 25 or 37 degrees C can be discriminated by alkylating the DNA with a tetranucleotide carrying a 4-[N-methyl-N-(2-chloroethyl)]aminobenzylethylamine residue at the 5'-terminal phosphate in the presence of a pair of flanking effectors, octanucleotide di-N-(2-hydroxyethyl)-phenazinium derivatives. The discrimination factor (ratio of the extent of the target modification in the perfect and mismatch-containing complexes) for a single mismatch in the tetranucleotide binding site at 25 degrees C varied between 4 and 500 depending on the type of mismatch and its location in the complex and exceeded 400 at 37 degrees C for all the investigated mismatches. The DNA target modification by the alkylating derivative of the 3'-estrone ester of tetranucleotide pCAGX (mean = C, T, A or G) was selective in the presence of a pair of hydrophobic effectors, octanucleotide 5'-cholesteryl-3'-phenazinium derivatives. The discrimination factors for 3'-terminal mismatches T.G, A.G, and G.G were 1,8,400, and 400, respectively.