Structural basis for a lethal mutation in U6 RNA

Results suggest that the mutational lethality of U80G is probably due to a structural rearrangement within the internal loop of the U6 RNA 3' intramolecular stem-loop region (ISL), leading to hyperstabilization of the structure and consequent non-melting of U6 ISL and not rearranging itself to interact with small nuclear RNA, U4.