PubReading [325] - pH-dependent sedimentation of DNA in the presence of divalent, but not monovalent, metal ions - C. England, L. K. Lewis et al.

Precipitation of DNA is performed frequently in molecular biology laboratories for the purpose of purification and concentration of samples and also for transfer of DNA into cells. Metal ions are used to facilitate these processes, though their precise functions are not well characterized. In the current study we have investigated the precipitation of double-stranded DNA by group 1 and group 2 metal ions. Double-stranded DNAs were not sedimented efficiently by metals alone, even at high concentrations. Increasing the pH to 11 or higher caused strong DNA precipitation in the presence of the divalent group 2 metals magnesium, calcium, strontium and barium, but not group 1 metals. Group 2 sedimentation profiles were distinctly different from that of the transition metal zinc, which caused precipitation at pH 8. Anal ...