Unwinding and rewinding of DNA

Shin, Y. A., and G. L. Eichhorn Interactions of metal ions with polynucleotides and related compounds. XI The reversible unwinding and rewinding of DNA by Zn2+ ions through temperature manipulation. Biochemistry 7, 1026 (1968). 

The results of Fig. 9 correlate remarkably well with the relative effectiveness of these metal ions in producing the various ligand reactions described for zinc. Of particular interest is that the different metal ions can bring about the unwinding and rewinding of DNA under very different conditions. The differences between zinc and other metal ions in their behavior in these ligand reactions have been discussed elsewhere. 

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