FIGURE 7.

SbnI forms dimers and tetramers in solution. A, purification of recombinant His₆-SbnI. Various samples during the purification process are run through a polyacrylamide gel, starting with pre-column (load), flow-through (flow), wash fraction (wash), and elution fractions 1–4. The identity of the three bands labeled with an asterisk was confirmed as SbnI using MALDI. B, size exclusion chromatography of SbnI. Chromatogram represents size exclusion data of SbnI run in 300 mm ammonium formate, pH 7.4, at flow rate of 0.2 ml/min across Superdex 200 FPLC column. Elution volumes of known protein standards are shown at the top and are used to generate a standard curve (inset). C and D, sedimentation velocity-analytical ultracentrifugation was performed on SbnI run in 300 mm ammonium formate, pH 7.4, 100 mm NaCl. C, 10 mm DTT was included.