Purification and characterization of Qβ replicase with a His-tag

A His-tag was added to the C-terminal of Qβ replicase, an RNA-dependent RNA polymerase of RNA coliphage Qβ, to facilitate enzyme purification. The purified His-tagged enzyme assumed almost the same template specificity as the wild type purified by a conventional method when MDV-poly(+) RNA or Qβ RNA was used as the template. Here, we showed the efficiency of the approach surmounts the present available ones. The availability of Qβ replicase of quality affords its implementation for the synthesis and amplification of RNA molecules as well as further elucidation on the molecular mechanism of the enzyme reaction.