Department of Chemistry and RINS, Gyeongsang National University, Jinju, Gyeongnam 660-701, Republic of Korea.
FEBS Lett. 2011 Mar 9;585(5):772-8. doi: 10.1016/j.febslet.2011.01.043. Epub 2011 Feb 4.
The human DNA-dependent activator of IFN-regulatory factor (DAI) protein, which activates the innate immune response in response to DNA, contains two tandem Z-DNA binding domains (Zα and Zβ) at the NH(2) terminus. The hZβ(DAI) structure is similar to other Z-DNA binding proteins, although it demonstrates an unusual Z-DNA recognition. We performed NMR experiments on complexes of hZβ(DAI) with DNA duplex, d(CGCGCG)(2), at a variety of protein-to-DNA molar ratios. The results suggest that hZβ(DAI) binds to Z-DNA via an active-di B-Z transition mechanism, where two hZβ(DAI) proteins bind to B-DNA to form the hZβ(DAI)-B-DNA complex; the B-DNA is subsequently converted to left-handed Z-DNA. This novel mechanism of DNA binding and B-Z conversion is distinct from Z-DNA binding of the human ADAR1 protein.
人 DNA 依赖性干扰素调节因子激活蛋白（DAI），可在 DNA 存在的情况下激活先天免疫反应，其氨基末端含有两个串联的 Z 型 DNA 结合域（Zα 和 Zβ）。hZβ（DAI）结构与其他 Z 型 DNA 结合蛋白相似，尽管它表现出一种不寻常的 Z-DNA 识别方式。我们在各种蛋白与 DNA 摩尔比下，对 hZβ（DAI）与 DNA 双链体 d（CGCGCG）（2）的复合物进行了 NMR 实验。结果表明，hZβ（DAI）通过一个主动的双 Z 转变机制与 Z-DNA 结合，其中两个 hZβ（DAI）蛋白与 B-DNA 结合形成 hZβ（DAI）-B-DNA 复合物；随后，B-DNA 被转化为左手 Z-DNA。这种独特的 DNA 结合和 B-Z 转换机制与人类 ADAR1 蛋白的 Z-DNA 结合不同。
