Contributions and competition of Mg²⁺ and K⁺ in folding and stabilization of the Twister ribozyme

Radial distribution functions (RDF) of Mg²⁺ (A,C,E) and K⁺ (B,D,F) around NBPOs, Ade-N7/Gua-N7, and O2/O4/O6 atoms of nucleobases that participate or do not participate in helical structures, respectively. From left to right the plots correspond to RDFs calculated at native state (RC = 14–16), inflection point (RC = 19–21), and unfolded state (RC = 38–40) for 100 mM MgCl₂. Red line—helical region; blue line—nonhelical region.