Fig. 4.

Activation of PKR by the PBM decoy peptide. (A) Activation of PKR purified from human cells. PKR activation assays were done in the presence or the absence of the peptides used in Fig. 2B. Lane 1, no addition; lane 2, 100 nM MBP-3; lane 3, 100 μM WT peptide; lane 4, 500 μM WT peptide; lane 5, 1 mM WT peptide; lane 6, 1 mM D328A mutant peptide; lane 7, 1 mM D333A mutant peptide. (B) Activation of PKR purified from E. coli. Lanes 1–5 were the same as in A except for the source of PKR. PKR at 100 nM was used in all reactions.