Figure 2
(a) SDS–PAGE following purification of RepSTK1(1–269). Lane S, size markers (as Fig. 1 ); lane 1, whole cells following induction of expression with IPTG; lane 2, cleared lysate prior to loading the HisTrap column; lane 3, unbound material; lane 4, peak fraction following elution from HisTrap column. F shows the position of the purified fragment. Further purification steps were required to remove nonspecific nuclease activity from the protein preparations, but did not improve the purity of the sample as assessed by SDS–PAGE. (b) SEC–MALLS trace for RepSTK1(1–269) monitored by absorbance at 280 nm (blue). The protein elutes at a volume of 10.5 ml corresponding to an apparent molecular mass of 60 kDa and the absolute molecular mass (red) calculated from the MALLS signal corresponds to a mass of 62 kDa. |