OLE RNA (Ornate Large Extremophilic RNA) is a conserved RNA structure present in certain bacteria. The RNA averages roughly 610 nucleotides in length. The only known RNAs that are longer than OLE RNA are ribozymes such as the group II intron and ribosomal RNAs. The exceptional length and highly conserved structure of OLE RNA prompted the hypothesis that OLE RNA could be a ribozyme, or otherwise perform an intricate biochemical task. X-ray structural studies revealed key elements that help specifically recognise the OapB protein in Bacillus halodurans.