Noncanonical G(syn)-G(anti) base pairs stabilized by sulphate anions in two X-ray structures of the (GUGGUCUGAUGAGGCC) RNA duplex.

ABSTRACT: The structures of two crystal forms of the RNA 16-mer with the sequence GUGGUCUGAUGAGGCC, grown in the presence of a high concentration of sulphate ions, have been determined using synchrotron radiation at 1.4- and 2.0-A resolution. RNA with this sequence is known as one of the two strands of the noncleavable form of the hammerhead ribozyme. In both crystal structures, two G(syn)-G(anti) noncanonical base pairs are observed in the middle of a 14 base-pair (bp) duplex having 5'-dangling GU residues. Both structures contain sulphate anions interacting with the G-G bp stabilizing G in its syn conformation and bridging the two RNA strands. In both cases the interactions take place in the major groove, although the anions are accommodated within different helix geometries, most pronounced in th

SUBMITTER: Rypniewski W 

PROVIDER: S-EPMC2525959 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature