NMR study of hydrogen exchange during the B–Z transition of a DNA duplex induced by the Zα domains of yatapoxvirus E3L

The Yaba-like disease viruses (YLDV) are members of the Yatapoxvirus family and have double-stranded DNA genomes. The E3L protein, which is essential for pathogenesis in the vaccinia virus, consists of two domains: an N-terminal Z-DNA binding domain and a C-terminal RNA binding domain. The crystal structure of the E3L orthologue of YLDV (yabZαE3L) bound to Z-DNA revealed that the overall structure of yabZαE3L and its interaction with Z-DNA are very similar to those of hZαADAR1. Here we have performed NMR hydrogen exchange experiments on the complexes between yabZαE3L and d(CGCGCG)2 with a variety of protein-to-DNA molar ratios. This study revealed that yabZαE3L could efficiently change the B-form helix of the d(CGCGCG)2 to left-handed Z-DNA via the active-mono B–Z transition pathway like hZαADAR1.