title: Different behavior of the octadeoxynucleotides d(A-T)4 and d(T-A)4 at high concentrations of cesium fluoride.
abstract: High CsF concentrations induce a zig-zag double helix, which we call X-DNA, in poly d(A-T) and also in the octadeoxynucleotide d(T-A)4 while d(A-T)4 remains fixed in a B-DNA form. Intermolecular contacts promote the B-X isomerization of the former oligonucleotide but induce aggregation of the latter. This indicates that there is an intramolecular factor, presumably base stacking in the T-A steps, stabilizing the X-DNA conformation.
mesh_terms: D002586:Cesium / Q000494:pharmacology*; D002942:Circular Dichroism; D005459:Fluorides; D007536:Isomerism; D009690:Nucleic Acid Conformation / Q000187:drug effects*; D011067:Poly dA-dT; D011089:Polydeoxyribonucleotides; D011108:Polymers
chemical_list: D011089:Polydeoxyribonucleotides; D011108:Polymers; D002586:Cesium; D011067:Poly dA-dT; D005459:Fluorides; C027754:cesium fluoride