Figure 1.
(A) Primary amino acid sequence of the wild-type N-terminal U1A RNA Recognition Motif (RRM). Structural features of U1A are highlighted in blue. Residues mutated in this work are highlighted in red. (B) U1A/U1hpII complex (PDB: 1URN). The b2-b3 loop and key residues that are mutated in this work are highlighted and annotated. (C) Space-filling model of U1A b2-b3 loop residues protruding through the U1hpII RNA loop. (D) Hydrogen bond network formed between U1A residues Asn15, Asn16, and Glu19 and U1hpII bases U2, U3, and G4. These contacts contribute to the source of sequence selective recognition of U1hpII by U1A. Hydrogen bonds are represented as black dashed lines.