title: Temperature-induced perturbations in the circular dichroic spectrum of the synthetic polymer poly[d(G-C)].
abstract: The effect of increasing temperature on the double-helical synthetic DNA polymer poly[d(G-C)] with alternating base sequence, was studied by ultraviolet absorbance and circular dichroic techniques. While a cooperative hyperchromic effect was noticed in the ultraviolet absorbance spectrum above a temperature of 70 degrees C, an inversion of the circular dichroic spectrum was observed at a similar temperature range. On cooling to room temperature, the spectrum was reversed to the initial one. These observations, first reported here, are tentatively attributed to a conformational change of the polymer, from the right-handed double helix to the left-handed single strands, prior to complete denaturation.
mesh_terms: D002942:Circular Dichroism; D003841:Deoxycytidine; D006147:Guanine; D009690:Nucleic Acid Conformation; D011089:Polydeoxyribonucleotides; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature
chemical_list: D011089:Polydeoxyribonucleotides; D003841:Deoxycytidine; D006147:Guanine