Methods for purification of an RNA phage Qβ were described. From the experiments using this purified sample, it was shown that the virus had a sedimentation constant of 85S and a particle weight of 4.5×10
6. Furthermore, the results of chemical analysis showed that the RNA content of this virus was about 26%. From this value the molecular weight of phage RNA was calculated as 1.2×10
6.
Morphologically, the virus has a polyhedral structure with a diameter of about 24mμ.
The bases of Qβ RNA are present in the ratio Adenine; Guanine; Cytosine; Uracil=22.4; 24.5; 23.5; 29.6. GC content of Qβ RNA calculated from these values is about 48.0%. It is rather different from those values in other known RNA phages such as MS2 and f2. In addition, Qβ and MS2 are banded separately in CsCl equilibrium density gradient centrifugation. These facts and the serological properties of these two phages suggest that Qβ and MS2 belong to different group.
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