US chemists have used click chemistry to make molecules that mimic peptides. 

Peptide mimics, dubbed peptoids, can incorporate all the sophisticated biological activity of peptides. But peptoids are not as easily broken down in the body as peptides, opening up potential medical applications.

Kent Kirshenbaum and colleagues at New York University came up with a method for making peptoids that allowed the chemists to selectively position biologically active groups along the molecule's backbone.

They started by tethering the first piece of the molecule to a solid support. Then they built up the molecule by sequentially adding units to the end of the chain. They say this approach means that biologically active groups can be added at predetermined positions along the molecule, and should also allow the synthesis to be automated. 

The researchers attached the bioactive parts to the peptoid by the copper-catalysed click chemistry reaction between an azide and an alkyne. They added either the azide or the alkyne unit to the peptoid backbone first. Then they added the bioactive group (bearing the appropriate coupling partner) to the solution, and the two connected together. Azide and alkyne groups react with each other very efficiently, but don't react with any of the other functionality found in the rest of the molecule. 

Kirshenbaum said the possible applications of peptoids are extremely broad, from energy transduction to information storage. 'Even if we can only begin to recapitulate a small fraction of the capabilities of biomacromolecules, the opportunities are almost limitless,' he said.  

James Mitchell Crow