ECD (mdeg) of DNA–Mn2+ complexes at 30 mM NaCl. The curves represent DNA spectra at different manganese concentrations in sequence: 1, 0 mM MnCl2; 2, 0.10 mM (R = 0.067); 3, 0.25 mM (R = 0.17); 4, 1.00 mM (R = 0.67); 5, 2.50 mM (R = 1.7); 6, 10.00 mM (R = 6.7); 7, 50.00 mM (R = 33); 8, 250 mM (R = 170) MnCl2.