Key points are not available for this paper at this time.
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-32PATP. 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.
Kerr et al. (Sun,) studied this question.