Diversity and modularity of tyrosine-accepting tRNA-like structures

Domain architecture of tyrosine-accepting TLS RNAs. (A, B) Cartoon diagrams of the secondary structure of the tyrosine-accepting tRNA-like structures (TLS^Tyr) from the (A) anulavirus, bromovirus, cucumovirus, and oleavirus genera of Bromoviridae and (B) hordeivirus genus of Virgaviridae. Helical elements are lettered according to previous literature (Ahlquist et al. 1981; Solovyev et al. 1996; Savenkov et al. 1998; Bonilla et al. 2021). The respective 5′ domains, consisting of the (A) E and B3 stem–loops or (B) R stem–loop, are boxed in gray. The secondary structure of the R domain of the hordeivirus TLS^Tyr was not experimentally probed before this study; the putative structure is shown. (C, D) Structural model of the BMV TLS in the C unbound (RNA-only; PDB ID: 7SAM) and (D) bound (RNA-tyrosine synthetase complex; PDB ID: 7SCQ) states with each domain labeled. The synthetase is not shown for clarity.