Sequencing of oligonucleotide phosphorothioates based on solid-supported desulfurization

Abstract
We described a solid-supported desulfurization procedure allowing easy access to the sequence analysis of oligonucleotide phosphorothioates. The described method is based upon selective removal of the 2-cyanoethyl phosphate protecting groups, followed by iodine-promoted desulfurization of the resulting phosphorothioate diesters. Automatic oxidation of oligonucleotide phosphorothioates, anchored via an ester linkage to a standard solid support (LCAA/CPG), is combined with Maxam-Gilbert solid-support sequencing. The overall procedure allows rapid simultaneous sequence analysis of several oligonucleotide analogs.