Base specific fractionation of double stranded DNA: affinity chromatography on a novel type of adsorbant

A material suitable for base-pair-specific "affinity chromatography" of double stranded DNA is described. The synthesis of this material involves two successive polymerization reactions yielding solid particles of cross-linked bisacrylamide to which base-pair-specific dyes are covalently attached by spacers of polyacrylamide chains of different length. Materials with immobilized A.T-specific malachite green or G.C-specific phenyl neutral red were used for base-pair-specific fractionation of sheared DNA from bacterial sources, as well as of higher molecular weight Calf thymus DNA or defined fragments of coliphage lambda DNA. The excellent resolving power of this method of "affinity chromatography" of nucleic acids is comparable only to DNA fractionation in buoyant density gradients in the presence of base-pair-specific ligands. A great advantage of this material is its simple handling and its chemical stability, which allows repeated re-use of the same column.