Effect of magnesium or calcium on the conformations of the topoisomers of dsMCs.

(A) Electrophoretic migration profile of the seven topoisomers in the presence of magnesium. Magnesium (10 mM) is present in the native polyacrylamide gel and in the running buffer. (B) Electrophoretic migration profile of the seven topoisomers in the presence of calcium. Calcium (10 mM) is present in the native polyacrylamide gel and in the running buffer. (C) Electrophoretic migration profile of the seven topoisomers on a native gel made in TBE 0.5x. The topoisomers differ by their relative linking number. In all figures, ΔLk ranges from 0 (T0 topoisomer, lane 1) to -6 (T-6 topoisomer, lane 7). Electrophoreses are performed at 4°C with buffer being recycled.