Crystallization and preliminary X-ray crystallographic studies on the bacteriophage phi6 RNA-dependent RNA polymerase

The RNA-dependent RNA polymerase (P2) from bacteriophage Phi6 has been cloned and the protein overexpressed in Escherichia coli to produce an active enzyme. A fully substituted selenomethionyl version of the protein has also been produced. Crystals of both proteins have been grown; most belong to the monoclinic space group P2(1), with unit-cell parameters a = 105.9, b = 94.0, c = 140.9 A, beta = 101.4 degrees, but some are trigonal (space group P3(1) or P3(2)), with unit-cell parameters a = b = 110.1, c = 159.4 A, gamma = 120 degrees. Both crystal forms occur in the same crystallization drop and are morphologically indistinguishable. Native data sets have been collected from both types of crystals to better than 3 A resolution.