ABSTRACT
The first indications on the existence of a specific maturation protein, or maturase, or A protein, or RNA-protecting protein, or IIa protein, or A2 protein have been received from the RNA phage genetics. This chapter demonstrates how the early speculations were converted into the strong biochemical knowledge. The story of the isolation, characterization, and sequencing of the maturation proteins is narrated. The data on the maturation protein homology are presented. The recent data on the three-dimensional structure of the Qβ A2 protein are demonstrated in detail. A special attention is devoted to the unexpected lysis function of the Qβ A2 protein, fine mechanisms of which have been identified recently.
