Polynucleotide complexes melting

Like double-stranded DNA, synthetic polynucleotide complexes containing complementary bases show cooperative melting curves, i.e., the property studied (UV absorption, optical activity, viscosity, etc.) shows a sharp transition at a specific temperature. This Tm depends on ionic strength and, to a certain degree, on pH. If the temperature is increased above the Tm, however, a further continuous variation in the property studied will be observed. It is only in recent years that an understanding of such noncooperative phenomena is emerging. Here the studies of oligomers by CD and NMR were of critical importance. 

Interactions of the paft copolymers of adenine and thymine on linear and branched polyethylenimine with polynucleotides, poly A and poly U, were studied.57 From the Job plots58 of the A-PEI/T-PEI system at pH 7.4, formation of the complex was observed, the overall stoichiometry of the latter being 1 1 hypochromicity of the 1 1 complex was about 16%. The melting profiles are reversible upon heating and cooling. 

In the present tables it was attempted to assemble the maximum of data on melting temperatures of polynucleotides and their complexes in the literature. 

Table 5 (section 3.2.2.4) contains melting temperatures of complexes between the same polynucleotide (homo-complexes). This table contains double, triple and four stranded complexes. Also included ate several polynucleotides which have no structure which is indicated as that... 

---