Metal ion dependence of cooperative collapse transitions in RNA.

摘要: Abstract Positively charged counterions drive RNA molecules into compact configurations that lead to their biologically active structures. To understand how the valence and size of cations influences collapse transition in RNA, small-angle X-ray scattering was used follow decrease radius gyration (Rg) Azoarcus Tetrahymena ribozymes different cations. Small, multivalent induced both more efficiently than did monovalent ions. Thus, cooperativity depends on counterion charge density. Singular value decomposition curves showed folding smaller thermostable ribozyme is well described by two components, whereas larger involves at least one intermediate. The ion-dependent persistence length, extracted from distance distribution vectors, shows less flexible midpoint low-charge-density ions high-charge-density We conclude formation sequence-specific tertiary interactions overlaps with neutralization phosphate charge, while requires additional counterions. stability structure determines its sensitivity