Peptide tags that encode chemical libraries could revolutionise drug discovery

For the first time, small strings of amino acids have been used to encode enormous chemical libraries of over 40,000 compounds. Thanks to these peptide libraries, researchers were able to identify a number of drug candidates for cancer.

The concept of chemical libraries is popular in drug discovery. ‘It relies on two key components – encoding and decoding information,’ explains joint first author Nathalie Grob from the Massachusetts Institute of Technology in the US. It works like barcodes : after attaching unique ‘tags’ to a range small molecules, researchers investigate their affinity with proteins previously associated with known diseases. Then, the best binders are identified by simply reading the tag. Usually, chemists tag compounds with DNA fragments, which enables quick and simple separation and interrogation of the library. But DNA limits the possibilities, mostly because of the sensitivity and incompatibility of nucleotides with certain chemicals and catalysts – such as strong acids, transition metals, even radicals.