Sequence discrimination of the Zα domain of human ADAR1 during B–Z transition of DNA duplexes

Abstract

The Zα domain of human ADAR1 (Zα ADAR1) preferentially binds Z-DNA rather than B-DNA with high binding affinity. Zα ADAR1 binds to the Z-conformation of both non-CG-repeat DNA duplexes and a d(CGCGCG) 2 duplex similarly. We performed NMR experiments on complexes between the Zα ADAR1 and non-CG-repeat DNA duplexes, d(CACGTG) 2 or d(CGTACG) 2, with a variety of protein-DNA molar ratios. Comparison of these results with those from the analysis of d(CGCGCG) 2 in the previous study suggests that Zα ADAR1 exhibits the sequence preference of d(CGCGCG) 2 ≫ d(CACGTG) 2 > d(CGTACG) 2 through multiple sequence discrimination steps during the B–Z transition.