The binding selectivity of ADAR2's dsRBMs contributes to RNA-editing selectivity.
ADAR2 is an RNA editing enzyme that deaminates adenosines in certain duplex structures. Here, we describe the role of its RNA binding domain, consisting of two copies of a common dsRNA binding motif (dsRBM), in editing site selectivity. ADAR2's dsRBMs bind selectively on a duplex RNA that mimics the Q/R editing site in the glutamate receptor B-subunit pre-mRNA. This selectivity is different from that of PKR's dsRBM I, indicating that dsRBMs from different proteins possess intrinsic binding selectivity. Using directed hydroxyl radical cleavage data, molecular models were developed that predict important recognition surfaces on the RNA for identified dsRBM binding sites. Blocking these surfaces by benzyl modification of guanosine 2-amino groups impeded RNA-editing, demonstrating a correlation between deamination efficiency by ADAR2 and selective binding by its dsRBMs. In addition, the editing activity of a mutant of ADAR2 lacking dsRBM I on N(2)-benzylguanosine-modified RNA suggests the location of the dsRBM I binding site that leads to editing at the GluR-B Q/R site.
Stephens
Olen M
OM
Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA.
Haudenschild
Brittany L
BL
Beal
Peter A
PA
D000243:Adenosine Deaminase / Q000378:metabolism*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites / Q000502:physiology; D003641:Deamination; D024202:Electrophoretic Mobility Shift Assay; D006151:Guanosine / Q000031:analogs & derivatives* / Q000502:physiology; D006801:Humans; D017665:Hydroxyl Radical / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding / Q000502:physiology; D017393:RNA Editing / Q000502:physiology*; D012330:RNA, Double-Stranded / Q000378:metabolism*; D016601:RNA-Binding Proteins; D016415:Sequence Alignment; D013379:Substrate Specificity; D019892:eIF-2 Kinase / Q000502:physiology
C492556:N2-benzylguanosine; D012330:RNA, Double-Stranded; D016601:RNA-Binding Proteins; D006151:Guanosine; D017665:Hydroxyl Radical; D019892:eIF-2 Kinase; C567955:ADARB1 protein, human; D000243:Adenosine Deaminase