Cooperative oligonucleotides in purification of cycle sequencing products

Nucleic acid hybridization is an essential component in many of today's sta ndard molecular biology techniques. In a recent study, we investigated whet her nucleic acid capture could be improved by taking advantage of stacking hybridization, which refers to the stabilizing effect that exists between o ligonucleotides when they hybridize in a contiguous tandem fashion. Here, w e describe a specific approach for purification of sequencing products usin g cooperative probes that hybridize to single-strand targets where one of t he probes has been coupled to a magnetic bead. This approach has been devel oped for standard sequencing primers and has been applied to shotgun plasmi d libraries. The cooperative probes have been designed to anneal within the common vector sequence and to avoid copurification of non extended sequenc ing primers and misprimed sequencing products. The reuse of magnetic beads, together with salt independent elution, makes the approach suitable for hi gh-capacity capillary electrophoresis instruments.