Crystal structure of a poxvirus-like zalpha domain from cyprinid herpesvirus 3.

Zalpha domains are a subfamily of the winged helix-turn-helix domains sharing the unique ability to recognize CpG repeats in the left-handed Z-DNA conformation. In vertebrates, domains of this family are found exclusively in proteins that detect foreign nucleic acids and activate components of the antiviral interferon response. Moreover, poxviruses encode the Zalpha domain-containing protein E3L, a well-studied and potent inhibitor of interferon response.