ABSTRACT
The RNA phage replicases played an extraordinary role in the global development of molecular biology and molecular evolution. These unique enzymes unveiled for the first time the global overlapping of the translation and transcription mechanisms in live organisms. The intriguing history of the unexpected discoveries in the replicase field is narrated. The specific enzymatic features of the most studied and broadly used Qβ replicase are compiled. The fine structure of the Qβ replicase is presented in detail, with a special emphasis on the cellular counterparts of the phage-specific subunit within the whole enzyme, namely, the ribosomal protein S1, elongation factors Tu and Ts, and RNA chaperone Hfq. The high-resolution structure of the Qβ replicase and its components is illustrated by the most recent findings. The hard history is recounted about the elucidation of the non-Allolevivirus replicases purified from E. coli cells infected with the phages f2, MS2, GA, and R17.
