Abstract
The thermal stabilities of RNA:DNA hybrids are substantially greater than those of DNA:DNA duplexes in aqueous electrolyte solutions containing high concentrations of formamide. Association rates to form DNA:DNA duplexes and DNA:RNA hybrids have been measured in these solvents. There is a temperature range in which DNA:DNA rates are negligible and RNA:DNA rates close to optimal.
Highlights
Aqueous formamide is a useful solvent for studies of the rates of RNA:DNA and DNA:DNA association reactions because the reactions proceed at a much lower temperature than in pure aqueous solvents [1,2]
There is a broad maximum in the temperature dependence of the rate of association of complementary DNA strands, with a center about 250 below the midpoint, T1/2d, of the thermal melting transition [3]. (We follow Hamaguchi and Geiduschek [4] and denote by T1/2d the midpoint of the thermal melting curve of a duplex polynucleotide measured at ambient temperature and by T1/2i the midpoint of the irreversible (HAP or ribonuclease assay) melting curve.) In the absence of further information, Tl/2d-2S is commonly chosen as the optimal temperature for an RNA:DNA reaction
Their data support the view that RNA:DNA hybrids are stabilized relative to DNA:DNA duplexes by formamide and that the optimum temperature for reassociation is greater than T1/2-25 v Schmeckpeper and Kirby [6] have presented evidence that the optimum temperature for RNA:DNA
Summary
Aqueous formamide is a useful solvent for studies of the rates of RNA:DNA and DNA:DNA association reactions because the reactions proceed at a much lower temperature than in pure aqueous solvents [1,2]. Birnstiel et al, [5] have measured the formation rate and thermal dissociation temperature of RNA:DNA hybrids in 50% formamide solvents with the DNA bound to a membrane filter.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
