Nature Chem. Biol. doi:10.1038/nchembio.211 (2009)

By tagging small molecules with short, double-stranded DNA fragments, Barry Morgan and his colleagues at GlaxoSmithKline in Waltham, Massachusetts, have created a collection of 800 million compounds that can be screened much faster than conventional chemical libraries.

Researchers can screen for ligands that bind to a protein target and then identify the new molecule by sequencing the DNA 'barcode' attached. As a proof of concept, the authors probed their DNA-tagged library — which is at least two orders of magnitude larger than a typical small-molecule library — for enzyme-blocking drug leads and pulled out novel inhibitors of two kinases.