The molecular dynamics study of the RNA-binding domain of ADAR2 bound to dsRNA

J. Pasulka, J. Koča and R. Štefl

National Centre for Biomolecular Research, Faculty of Science, Masaryk

University, Kotlarska 2, Brno, 611 37, Czech Republic

Like RNA splicing, RNA editing alters the sequence of an RNA from that encoded in the DNA. Typically, a single RNA splicing reaction removes a large block of contiguous sequence, whereas each RNA editing reaction changes only one or two nucleotides. Therefore splicing is a cut-and-paste mechanism whereas editing is one of fine-tuning.

RNA editing by adenosine deamination is catalyzed by members of an enzyme family known as adenosine deaminases that act on RNA (ADARs). ADARs are RNA editing enzymes that target double-stranded regions of nuclear-encoded RNA. ADARs are also interesting in regard to the remarkable double-stranded structures of their substrates and how enzyme specificity is achieved with little regard to sequence.

ADARs from all organisms have a common domain structure that includes variable numbers of double-stranded RNA (dsRNA) binding motifs (dsRBMs) followed by a highly conserved C-terminal catalytic domain. We focused on the N-terminal non-catalytic domain ADAR2, which recognizes the dsRNA with A-C mismatches. Using MD simulations, we study the role of mismatches and their flexibility for the formation of dsRBM-RNA complexes.