Structure and function of Zalpha, a Z conformation-specific nucleic acid binding domain

Right-handed B-DNA is a predominant form of natural DNA and used for the structural support of genetic information. Nevertheless, DNA can assume many different shapes. Left-handed Z-DNA is one of well-known non-B-DNA structures. An increasing number of studies show direct connections between Z-DNA and its potent roles in biological processes. The discovery of the proteins with Z-DNA binding domain(s), Zα, provides new opportunities to elucidate the relevant biological function of Z-DNA in biological systems. Thus, a great deal of recent researches has focused on questions surrounding Z-DNA and its binding proteins in vivo. In this review, we compare structures of Zα domains from various Z-DNA binding proteins and discuss their conformational specificity adapted from the common fold that prevalently used by many B-DNA binding proteins. In addition, we summarize recent developments regarding the biological roles of Z-DNA and Z-DNA binding proteins.