Studies of the temperature-dependent conformation and phase separation of polyriboadenylic acid solutions at neutral pH

摘要: Abstract The conformation of polyriboadenylic acid (poly A) in aqueous solutions at neutral pH has been investigated under “ideal”, Θ solvent conditions, as a function temperature. studies were carried out on fractions well-defined molecular weight obtained by reversible phase separation the polymer sodium chloride more concentrated than 1 m . Under such poly A is soluble low and high temperatures, but only partially miscible range centered 35 to 40 °C. extent varies with weight, salt concentrations. upper lower temperatures for solvents concentrations from 1.33 derived diagrams. Light-scattering experiments yielded weights, radii gyration second virial coefficients ( 2 ) several various concentrations, temperature −2 62.4 At fixed concentration, vanished two that solvent. In this way it was possible obtain values radius which unperturbed effects, thus separating long-range solvent-dependent influences short-range interactions due base stacking. sedimentation velocity viscosity behavior concentration also studied. -NaCl, both coefficient intrinsic vary M 0.5 quite close results show forms highly extended structure rapidly disrupted fraction bases stacks falls below unity. observations are consistent existence formed non-co-operative process.