Herbert A, Lowenhaupt K, Spitzner J, Rich A
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA.
Proc Natl Acad Sci U S A. 1995 Aug 1;92(16):7550-4. doi: 10.1073/pnas.92.16.7550.
A M(r) 140,000 protein has been purified from chicken lungs to apparent homogeneity. The protein binds with high affinity to a non-BNA conformation, which is most likely to the Z-DNA. The protein also has a binding site for double-stranded RNA (dsRNA). Peptide sequences from this protein show similarity to dsRNA adenosine deaminase, an enzyme that deaminates adenosine in dsRNA to form inosine. Assays for this enzyme confirm that dsRNA adenosine deaminase activity and Z-DNA binding are properties of the same molecule. The coupling of these two activities in a single molecule may indicate a distinctive mechanism of gene regulation that is, in part, dependent on DNA topology. As such, DNA topology, through its effects on the efficiency and extent of RNA editing may be important in the generation of new phenotypes during evolution.
一种分子量为140,000的蛋白质已从鸡肺中纯化至表观均一。该蛋白质与一种非B型核酸构象具有高亲和力结合，这种构象很可能是Z-DNA。该蛋白质还具有双链RNA（dsRNA）的结合位点。来自这种蛋白质的肽序列显示出与dsRNA腺苷脱氨酶相似，dsRNA腺苷脱氨酶是一种将dsRNA中的腺苷脱氨形成肌苷的酶。对这种酶的检测证实，dsRNA腺苷脱氨酶活性和Z-DNA结合是同一分子的特性。这两种活性在单个分子中的偶联可能表明一种独特的基因调控机制，该机制部分依赖于DNA拓扑结构。因此，DNA拓扑结构通过其对RNA编辑效率和程度的影响，可能在进化过程中产生新表型方面具有重要作用。
