Biochemical characterization and preliminary X-ray crystallographic study of the domains of human ZBP1 bound to left-handed Z-DNA

ZBP1 is involved in host responses against cellular stresses, including tumorigenesis and viral infection. Structurally, it harbors two copies of the Zα domain containing the Zα motif, at its N terminus. Here, we attempted to characterize the Z-DNA binding activities of two Zα domains in the human ZBP1, hZα_ZBP1 and hZβ_ZBP1, using circular dichroism (CD). Our results indicated that both hZα _ZBP1 and hZβ_ZBP1 are viable Z-DNA binders, and their binding activities are comparable to those of previously-established Zα domains. Additionally, we crystallized hZβ_ZBP1 in a complex with Z-DNA, d(TCGCGCG)₂. The crystal diffracted to 1.45 Å, and belongs to the P2₁2₁2₁ space group, with the unit-cell parameters: a = 29.53 Å, b = 58.25 Å, and c = 88.61 Å. The delineation of this structure will provide insight into the manner in which diverse Zα motifs recognize Z-DNA.