(A) Control of Nt.CviPII expression. Soluble extracts from equivalent induced (upper panel) and un-induced cultures (lower panel) were loaded on an SP FF column, eluted with a linear gradient of 0.1–1 M NaCl, and fractions were assayed for activity. (B) About 0.5 μg of pUC19 was incubated with 1 U of Nt.CviPII at the designated temperature for 1 h. Reactions were stopped and analyzed by electrophoresis on a 1.5% agarose gel. (C) Nt.CviPII-cleaved pUC19 and ss-M13 phage DNAs were analyzed by electrophoresis on a 6% PAG with 7 M urea. I, input; FT, flow-through; N, nicked pUC19; L, linearized pUC19; S, supercoiled pUC19; 100 bp, 100 bp DNA size marker; and LMW, low molecular weight DNA size marker.