High-speed atomic force microscopy and 3D modeling reveal the structural dynamics of ADAR1 complexes.

Targeting abnormal dysregulation of adenosine-to-inosine deamination by ADAR enzymes offers a promising therapeutic strategy in cancer research. However, the development of effective inhibitors is impeded by the incomplete structural information on ADAR1 complexes. In this study, we employ a combination of computational 3D modeling and high-speed atomic force microscopy to elucidate the atomic and molecular dynamics of ADAR1. Two distinct interface regions (IFx and IFy) on the surface of the deaminase domain and oligomerization structural models are identified. Single-molecule-level insights into the structural dynamics of ADAR1 reveal the oligomerization of ADAR1 monomers through the self-assembly of deaminase domains. In the presence of the substrate dsRNA, the N-terminal region, including RNA-binding domains, of ADAR1 dimer exhibits a controlled flexible conformation and promotes a stable dimeric interaction with dsRNA for RNA editing. These findings provide the basis for the development of targeted inhibitors to regulate ADAR1 activity in therapeutic applications.