Thermodynamic parameters of the binding of an oligo-alpha-thymidylate to its complementary oligo-beta-adenylate sequences.

The temperature dependence of the formation of a double-stranded complex between an oligo-alpha-thymidylate and its complementary sequence, beta-riboadenylate or beta-deoxyriboadenylate, was studied using circular dichroism and compared to the duplexes formed using an oligo-beta-thymidylate. Analysis of the melting profiles allowed us to determine the thermodynamic parameters (delta H, delta S and delta G) associated with the formation of the various duplexes. The order of the stability was found: alpha-dT:beta-dA approximately alpha-dt:beta-rA greater than beta-dT:beta-dA greater than beta-dT:beta-rA.