The structure of IMP3 RRM12 in complex with ACAC and CCCC RNAs. (A) Overall structure of IMP3 RRM12 and RNA ACAC. RRM1 (blue), RRM2 (green), linker (purple), and RNA (in sticks) are shown. Only RRM1 is involved in RNA binding. (B) Overall structure of IMP3 RRM12 and RNA CCCC. (C) Contact details between RRM1 β-sheet and cytosine C2 in IMP3 RRM12 and ACAC complex. (D) IMP3 RRM12 Y5A mutant disrupts the interaction between IMP3 RRM12 and RNA ACAC. (E) In the complex of IMP3 RRM12 with ACAC, the base of A3 stacks on the sidechain of Phe41 and forms a hydrogen bond with Ser73 on IMP3 RRM12 linker. (F) In the complex of IMP3 RRM12 with CCCC, the base of C3 stacks on the sidechain of Phe41.
