5'-Iodination of solid-phase-linked oligodeoxyribonucleotides.

5'-Iodinated oligodeoxyribonucleotides readily react with 3'-phosphorothioated DNA in the presence of a complementary template to yield a conjugate that is identical to natural DNA in every respect except that one oxygen atom in the phosphodiester backbone is replaced by a sulfur atom. The 5'-iodo group is easily converted to a variety of other functional groups and will quickly react with thiol-containing labels to yield stable thioether conjugates. This unit presents manual and automated procedures for converting the 5'-hydroxyl of protected CPG-bound oligodeoxyribonucleotides to an iodo group and for releasing and purifying the products.