Structural insights into RNA cleavage by a novel family of bacterial RNases.

Processing of RNA is a key regulatory mechanism for all living systems. We recently discovered a novel family of endoribonucleases that is conserved across all bacteria. Here, using crystallography, cryo-EM microscopy, biochemical, biophysical, and mass spectrometry techniques, we are able to shed light on a novel RNA cleavage mechanism in bacteria. We show that YicC, the prototypical member of this family, forms a hexameric channel that closes down on a 26-mer RNA substrate, and find that it cleaves across an RNA hairpin to generate several short fragments.