NMR Study on the Preferential Binding of the Z alpha Domain of Human ADAR1 to CG-repeat DNA Duplex

Abstract

The Z-DNA domain of human ADAR1 (Z(alpha ADAR1)) produces B-Z junction DNA through preferential binding to the CG-repeat segment and destabilizing the neighboring AT-rich region. 9 However, this study could not answer the question of how many base-pairs in AT-rich region are destabilized by binding of Z(alpha ADAR1). Thus, we have performed NMR experiments of Z(alpha ADAR1) to the longer DNA duplex containing an 8-base-paired (8-bp) CG-repeat segment and a 12-bp AT-rich region. This study revealed that Z(alpha ADAR1) preferentially binds to the CG-repeat segment rather than AT-rich region in a long DNA and then destabilizes at least 6 base-pairs in the neighboring AT-rich region for efficient B-Z transition of the CG-repeat segment.