Kerr I M, Brown R E
Proc Natl Acad Sci U S A. 1978 Jan;75(1):256-60. doi: 10.1073/pnas.75.1.256.
A low molecular weight inhibitor of cell-free protein synthesis effective at subnanomolar concentrations is formed on incubation of cytoplasmic extracts from interferon-treated cells with double-stranded RNA and ATP. It can be conveniently synthesized by incubating a poly(I).poly(C)-Sepharose-bound enzyme fraction from such cells with [3H]- or [alpha- or gamma-32P]ATP. The radioactive inhibitor has been characterized by its behavior on DEAE-Sephadex in the presence of urea and on the basis of the products obtained on enzymic, alkaline, and sequential degradation by periodate oxidation and beta elimination. Its structure appears to be pppA2'p5'A2'p5'A. We have found no evidence for any modification or abnormality other than the 2'-5' linkage. On occasion the inhibitor preparations have included what seems to be the corresponding dimer (pppA2'p5'A), tetramer [ppp(A2'p)3A], pentamer [ppp(A2'p)4A], and higher oligomers in decreasing amounts. The trimer, tetramer, and pentamer are similar in activity, but the dimer is less potent if active at all.
在将经干扰素处理的细胞的细胞质提取物与双链RNA和ATP一起温育时，会形成一种在亚纳摩尔浓度下有效的低分子量无细胞蛋白质合成抑制剂。通过将来自此类细胞的结合在聚（I）·聚（C）-琼脂糖上的酶组分与[³H]-或[α-或γ-³²P]ATP一起温育，可以方便地合成这种抑制剂。这种放射性抑制剂已通过其在尿素存在下在DEAE-葡聚糖上的行为以及基于酶促、碱性以及通过高碘酸盐氧化和β消除的顺序降解所获得的产物进行了表征。其结构似乎是pppA2'p5'A2'p5'A。除了2'-5'连接外，我们没有发现任何修饰或异常的证据。有时，抑制剂制剂中包含似乎是相应的二聚体（pppA2'p5'A）、四聚体[ppp(A2'p)3A]、五聚体[ppp(A2'p)4A]以及含量逐渐减少的更高寡聚体。三聚体、四聚体和五聚体的活性相似，但二聚体即使有活性也效力较弱。
