The crystal structure of a Polerovirus exoribonuclease-resistant RNA shows how diverse sequences are integrated into a conserved fold

Conserved interactions involving J1/3_CN at the dimer interface. (A) Close-up on the region involving J1/3_CN (A44, G45, C46 in PLRV, and A40, G41, U42 in SCNMV) in both structures. For panels A–D, the PLRV structure on the left side is compared to the SCNMV on the right side. (B) Interaction network involving PLRV A44 (left) and SCNMV A40 (right). (C) Interaction network involving PLRV G45 (left) and SCNMV G41 (right). (D) C46 (PLRV)/U42 (SCNMV) are in the vicinity of a negatively charged region (in red) formed by the backbone atoms of P1 and P2. Iridium(III) hexammines are shown as blue spheres. (E,F) In vitro Xrn1 degradation assays of PLRV xrRNA WT and J1/3_CN mutants.