Comparison of RNA recognition by L1 domains. (A,B) Structure of L1 from Sulfolobus acidocaldarius in complex with a fragment of 23S rRNA from T. thermophilus (PDB code 1MZP). (C,D) Structure of L1 from M. jannaschii L1 in complex with a fragment of its mRNA (PDB code 1U63). (E,F) Structure of Utp30–rRNA complex in 90S preribosome. (G,H) Structure of Cic1–RNA complex in pre-60S preribosome (PDB code 3JCT). These structures are aligned by protein. The RNA duplexes contacted by domain I are colored in red; the other protein-binding regions of RNA are colored in blue. The proteins are shown in surface representation in B, D, F, and H and colored in yellow for the atoms that are within 4 Å of any RNA atoms.
