The chirality of a four-way helical junction in RNA.

We have used a novel electrophoretic approach to determine the chirality of a four-way helical junction in RNA. From our experiments we conclude that the handedness of the helical junction in the complete ribozyme is opposite to that found in the free junction and is therefore constrained by the interaction between the unpaired loops of the ribozyme.

The kink-turn motif in RNA is dimorphic, and metal ion-dependent.

The kink-turn (K-turn) is a new motif in RNA structure that was identified by examination of the crystal structures of the ribosome. We examined the structural and dynamic properties of this element in free solution. The K-turn RNA exists in a dynamic equilibrium between a tightly kinked conformation and a more open structure similar to a simple bulge bend.