The low ionic strength form of the sodium salt of poly(dm5C-dG) is a B DNA.
The low-salt Z form of poly(dm5C-dG) reported in the literature was shown to be due to minute amounts of bivalent cations. If the polymer was purified by dialysis against 1 mM EDTA, poly(dm5C-dG) showed the normal B form. No change in this B form was observed up to 0.8 M NaCl. Very small amounts of Mg2+ or Ca2+ (10(-6) to 10(-5) M) induced the characteristic Z form CD spectrum, which could easily and rapidly be reverted to B-DNA by addition of EDTA.
Woisard
A
A
Guschlbauer
W
W
Fazakerley
G V
GV
D002942:Circular Dichroism; D004247:DNA; D007700:Kinetics; D009690:Nucleic Acid Conformation; D009994:Osmolar Concentration; D011089:Polydeoxyribonucleotides; D012964:Sodium; D013056:Spectrophotometry, Ultraviolet
D011089:Polydeoxyribonucleotides; D004247:DNA; D012964:Sodium