Amide foldamer bites back
A polyamide that folds back on itself, biting its tail, to make a compact three dimensional structure has been stumbled across by researchers in the UK.
Christopher Hunter and his group from the University of Sheffield were investigating the properties of a family of oligoamides made from alternate isophthalic acid and bisaniline building blocks when they discovered the tailbiter; a foldamer whose structure is governed by a complex pattern of intramolecular hydrogen bonds.
Poorly understood foldamers might now be deciphered thanks to the tailbiter
'The folding of this molecule was an accidental discovery,' said Hunter. 'The compound was designed and synthesised for a different purpose, but it clearly displayed unusual behaviour in solution.'
Synthetic foldamers provide simple chemical models for the more complex behaviour of biological molecules like proteins. The three-dimensional structures adopted by flexible molecules determine their functional properties, especially in biological systems. But the folding mechanism is poorly understood, as is the relationship between chemical structure and three-dimensional shape.
The 1H NMR technique used by Hunter can identify molecular structure by giving high resolution information from changes in chemical shifts. Predicting structure and designing stable and reliable folded molecules are the main challenges now facing Hunter.
Offering a starting point for an investigation into the folding behaviour in a new and different class of compounds, the tailbiter molecule could help to establish rules to predict the folding of more complex systems.
C A Hunter, A Spitaleri and S Tomas, Chem. Commun., 2005, 3691 (DOI: 10.1039/b506093a)