Icd-II ncRNA motif
The icd-II non-coding RNA is an RNA motif proposed as a Strong Riboswitch Candidate. Icd-II ncRNA has been recognized by a comparative sequence analysis in GC-rich intergenic regions of bacteria, using a pipeline call Discovery of Intergenic Motifs PipeLine. Icd-II ncRNA has been located upstream of the icd gene, which codes for an NADP+-dependent isocitrate dehydrogenase enzyme. IDH is part of the citric acid cycle, and thus it participates in managing the carbon flux through this energy metabolism pathway. Icd-II ncRNA has been found in bacteria of the class beta proteobacteria, particularly in Polynucleobacter genus. Icd-II RNA secondary structure consists of a three-stem junction, where the ribosome binding site of the adjacent open reading frame is predicted to be involved in the first base-paired stem. It has been proposed that icd-II ncRNA can function as a riboswitch that regulates translation initiation of its associate ORF.