Reconstitution of Qβ Replicase Lacking Subunit α with Protein‐Synthesis‐Interference Factor i

We have isolated a form of Qβ replicase lacking subunit α and shown that it is deficient in the utilization of Qβ‐plus strand RNA as template but competent to utilize Qβ‐minus strands, poly(C) and “6‐S” RNA. The functional identity of subunit α and protein‐synthesis‐inhibition factor i was proven by their equivalent capacity to restore full Qβ RNA‐directed activity of α‐less replicase.