Sequence discrimination of the Z alpha domain of human ADAR1 during B-Z transition of DNA duplexes

Abstract

The Z alpha domain of human ADAR1 (Z alpha(ADAR1)) preferentially binds Z-DNA rather than B-DNA with high binding affinity. Z alpha(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 Z alpha(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 Za(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. (C)2010 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.