title: A-form to A'-form conformational switch of double helices in rat liver 5S and 5.8S rRNA. Solution X-ray scattering evidence and circular dichroic measurements.
abstract: The wide-angle X-ray scattering of rat liver 5S rRNA and 5.8S rRNA molecules showed significant differences in the positions of the scattering maxima when dissolved in Mg2+-containing Tris/HCl buffer or in Mg2+-depleted buffer. A comparison of the experimental curves with theoretical curves calculated from atomic coordinates of double-helical models proved a switch from A form to A' form of the double-helical regions within the molecules by changing the buffer conditions. This result was supported by circular dichroic measurements. The A to A' transition may have important consequences for RNA-protein interactions.
mesh_terms: D000818:Animals; D002021:Buffers; D055598:Chemical Phenomena; D002621:Chemistry; D002942:Circular Dichroism; D008099:Liver / Q000032:analysis*; D008958:Models, Molecular; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D012335:RNA, Ribosomal / Q000302:isolation & purification; D051381:Rats; D012542:Scattering, Radiation; D014965:X-Rays
chemical_list: D002021:Buffers; D012335:RNA, Ribosomal