Effect of glycerol on the separation of nucleosomes and bent DNA in low ionic strength polyacrylamide gel electrophoresis

We report that glycerol changes the separation characteristics of polyacrylamide nucleoprotein gels in which it is included as a stabilizing agent. Polyacrylamide gel electrophoresis fractionates DNA and nucleosomes according to net negative charge, mass and conformation. With glycerol included, fractionation seems to be largely based on particle mass and charge. The conformation factor in separation is progressively lost with increasing glycerol concentrations. Nucleosome positions on the same DNA fragment are no longer resolved, while the difference in electrophoretic mobility between core particles and nucleosomes carrying longer DNA becomes smaller and is eventually lost. The retardation of bent DNA is also much reduced. Using the differences in separation characteristics between glycerol-containing and regular nucleoprotein gels could be a new means to obtain information on macromolecules in solution.