Immunochemical analysis of the functions of the subunits of phage Qbeta ribonucleic acid replicase.

We have prepared rabbit gamma-globulins specifically directed against each of the bacterial host proteins required for the in vitro replication of RNA phage Qbeta RNA: the protein synthesis elongation factors EF-Tu and EF-Ts, the 30 S ribosomal protein S1, and the Qbeta "host factor". We have used these antibodies as specific probes to study the roles that these polypeptides play in the in vitro replication of Qbeta RNA by the Qbeta replicase as well as the poly(C)-directed synthesis of poly(G) by this enzyme. The poly(C)-directed reaction is much less sensitive to antibody inhibition than is the Qbeta RNA-directed reaction.