Methylmercury-induced sedimentation heterogeneity of T7 bacteriophage DNA

Single-stranded and methylmercurated T7 DNA is composed of two species as evidenced from the sedimentation pattern displayed during band-sedimentation in self-generating density gradients as well as during equilibrium-sedimentation in CS2SO4 density gradients. Under the given experimental conditions, viz., at pH 9.18 and in presence of 0.1 mM CH3HgOH, the two species band in CS2SO4 with a density difference of 0.008 g/ml. The ratio of the sedimentation coefficients of the two species is sw, 20 (fast)/sw, 20 (slow) = 1.63 at pH 9.18 and in presence of 1.6 mM CH3HgOH. Both native and denatured T7 DNA behave as monodisperse systems in the absence of CH3HgOH.