Structural analysis reveals three families of bacterial tRNA mimics

Comparative genomics has identified over 1,000 candidate structured RNA motifs, yet most remain functionally uncharacterized. Here, we combine crystallography, comparative analysis, and bacterial genetics to identify three families of bacterial tRNA-like RNAs. The skipping-rope RNA adopts an L-shaped fold resembling tRNA despite distinct secondary-structure connectivity and tertiary interactions. In Clostridioides difficile, the skipping-rope RNA RCd1 is abundantly expressed and processed into a highly stable RNA species. RCd1 overexpression suppresses sporulation, whereas its deletion enhances early spore formation, supporting a role in sporulation control. Guided by the skipping-rope structure, we identify a conserved architectural core and use it to recognize additional candidate tRNA mimics. Crystal structures of DUF2693-FD and salivarius-1 RNAs confirm a shared tRNA-like scaffold assembled through distinct interaction networks. Together, these findings expand the repertoire of bacterial tRNA mimics and establish a structural framework for recognizing shared architectures among uncharacterized ncRNAs, linking one such family to bacterial developmental regulation.