Effects of Mg2+ on the free energy landscape for folding a purine riboswitch RNA.

ABSTRACT: There are potentially several ways Mg2+ might promote formation of an RNA tertiary structure: by causing a general "collapse" of the unfolded ensemble to more compact conformations, by favoring a reorganization of structure within a domain to a form with specific tertiary contacts, and by enhancing cooperative linkages between different sets of tertiary contacts. To distinguish these different modes of action, we have studied Mg2+ interactions with the adenine riboswitch, in which a set of tertiary interactions that forms around a purine-binding pocket is thermodynamically linked to the tertiary "docking" of two hairpin loops in another part of the molecule. Each of four RNA forms with different extents of tertiary structure were characterized by small-angle X-ray scattering. The free ener

SUBMITTER: Leipply D 

PROVIDER: S-EPMC3507322 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature