Purification and characterization of Q beta replicase with a His-tag

A His-tag was added to the C-terminal of Q beta replicase, an RNA-dependent RNA polymerase of RNA coliphage Q beta, to facilitate enzyme purification. The purified His-tagged enzyme assumed almost the same template specificit y as the wild type purified by a conventional method when MDV-poly(+) RNA o r Q beta RNA was used as the template. Here, we showed the efficiency of th e approach surmounts the present available ones. The availability of Q beta replicase of quality affords its implementation for the synthesis and ampl ification of RNA molecules as well as further elucidation on the molecular mechanism of the enzyme reaction. (C) 2000 Elsevier Science B.V. All rights reserved.