A peptide is a molecule consisting of several amino acids linked together. They are similar to proteins – which are also comprised of chains of amino acids – but with shorter chains. Peptides can be used as probes to explore the structure and function of proteins, for example by attaching to a specific site on a protein, and acting as a 'label' for that site.

Dr Zigang Li and his team at Peking University have developed a new type of peptide probe that can selectively target cysteine – an amino acid that forms part of proteins. They made the probe by attaching two methionine linkers to a section of a peptide, and then attaching a cysteine group in between the linkers – using a bis-alkylation reaction – to form a macrocycle. This macrocycle then forms a 'warhead' that selectively attaches to any other cysteine group in the vicinity.

Dr Li says that this work represents a new method for synthesising new drugs to target various diseases. They hope that it will eventually provide potential cures for those suffering from previously untreatable diseases.

This article is free to read in our open access, flagship journal Chemical Science: Shuiming Li, Feng Yin and Zigang Li et al., Chem. Sci., 2019, Advance Article. DOI: 10.1039/C9SC00034H. You can access our 2019 ChemSci Picks in this article collection.