On account of renewed interest in triple-stranded nucleic acid complexes we are carrying out a comprehensive thermodynamic study of helix formation among DNA homopolymers containing adenine, thymine and uracil. We have completed a calorimetric and spectroscopic study of the behavior of the poly(dA-poly(dT) system in the realm of high uni-univalent salt concentration where we have found the conditions for formation of a new polynucleotide complex and two entirely new helix-helix transformation reactions. The role and extent of displacement of cations, anions and water in these processes has been examined. The details of this work are being prepared for publication.
Ross, Philip D; Howard, Frank B (2003) The thermodynamic contribution of the 5-methyl group of thymine in the two- and three-stranded complexes formed by poly(dU) and poly(dT) with poly(dA). Biopolymers 68:210-22 |