Predicted secondary structure of the intervening sequence (IVS I). The predicted secondary structure of the intervening sequences (IVS I) of the 23S ribosomal RNA in B. microti and Brucella sp. B01 (left), B. suis (middle) and O. anthropi (right). Arrows with a dark head represent conserved cleavage sites. Arrows with a thin head represent unconserved cleavage sites. In O. anthropi, only the lower part of the cleavage motif is present.