Condensate morphology statistics versus HU concentration for reactions with HU added to DNA before condensation. (A) Relative rod populations versus HU concentration for linear DNA condensed by PEG. Samples were 5 µM DNA bp, 125 mg/ml PEG 8000, 100 mM NaCl, 50 mM Tris-HCl, 1 mM EDTA (pH 7.8), and indicated concentration of HU dimer. (B) Relative rod populations versus HU concentration for linear (circle) and supercoiled DNA (triangle) condensed by spermidine. Samples were 5 µM DNA bp, 700 µM spermidine chloride, 0.33 × TE (pH 7.8), 15 mM NaCl and indicated concentrations of HU dimer. (C) Relative rod populations versus HU concentration for linear DNA condensed by spermine. Samples were 5 µM DNA bp, 15 µM spermine chloride, 0.33 × TE (pH 7.8), 15 mM NaCl and indicated concentrations of HU dimer. Dashed curves are best-fit curves from rod populations measured for corresponding experiments in which HU was added coincident with the condensing agent (see Figures 1–3 for details).