Mellits K H, Kostura M, Mathews M B
Cold Spring Harbor Laboratory, New York 11724.
Cell. 1990 Jun 1;61(5):843-52. doi: 10.1016/0092-8674(90)90194-j.
Adenovirus VA RNAL maintains protein synthesis by preventing activation of the double-stranded RNA (dsRNA)-dependent protein kinase DAI. There appears to be a single binding site for dsRNA on DAI, and this site is blocked by VA RNAl. VA RNAl binds to purified DAI and can be cross-linked to the enzyme by UV irradiation. To determine the relationship between DAI binding and VA RNAl structure and function, we examined the binding abilities of wild-type and mutant VA RNAs. In several cases, the ability to bind DAI efficiently in vitro did not correlate with function in vivo. Secondary structure analysis suggested that efficient binding requires an apical stem-loop structure, whereas inhibition of DAI activation requires the central domain of the VA RNA molecule. We propose that the duplex stem permits VA RNA to interact with the dsRNA binding site on DAI and inhibits activation by juxtaposing the central domain of the RNA with the enzyme's active site.
腺病毒VA RNA1通过阻止双链RNA（dsRNA）依赖性蛋白激酶DAI的激活来维持蛋白质合成。DAI上似乎存在一个dsRNA结合位点，而该位点被VA RNA1阻断。VA RNA1与纯化的DAI结合，并且可以通过紫外线照射与该酶交联。为了确定DAI结合与VA RNA1结构和功能之间的关系，我们检测了野生型和突变型VA RNA的结合能力。在几种情况下，体外有效结合DAI的能力与体内功能并不相关。二级结构分析表明，有效结合需要一个顶端茎环结构，而抑制DAI激活则需要VA RNA分子的中央结构域。我们提出，双链茎允许VA RNA与DAI上的dsRNA结合位点相互作用，并通过将RNA的中央结构域与酶的活性位点并列来抑制激活。
