The structure of an RNA dodecamer shows how tandem U-U base pairs increase the range of stable RNA structures and the diversity of recognition sites.
Lietzke, S.E., Barnes, C.L., Berglund, J.A., Kundrot, C.E.(1996) Structure 4: 917-930
- PubMed: 8805576 
- DOI: https://doi.org/10.1016/s0969-2126(96)00099-8
- Primary Citation of Related Structures:  
280D - PubMed Abstract: 
Non-canonical base pairs are fundamental building blocks of RNA structures. They can adopt geometries quite different from those of canonical base pairs and are common in RNA molecules that do not transfer sequence information. Tandem U-U base pairs occur frequently, and can stabilize duplex formation despite the fact that a single U-U base pair is destabilizing.
Organizational Affiliation: 
Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0215, USA.