CONFORMATIONAL SUB-STATES IN B-DNA

Theoretical studies of the sequence-dependent conformation of B-DNA have been carried out using Jumna, a helicoidal co-ordinate minimization algorithm. The results obtained for a series of six oligomers with repetitive sequences show that, with the exception of the homopolymers (dA)n · (dT) n and (dG) n · (dC) n, all sequences can adopt a variety of conformations characterized by considerable changes in helicoidal parameters and also in sugar puckers which adopt C2′-endo (falling into 2 classes) or, in the case of pyrimidine nucleotides, O1′-endo forms. These studies lead to an improved understanding of the role of base sequence on DNA conformation and point to a number of interesting correlations between the various structural parameters describing the double helix. © 1992.