The effect of neat ionic liquid on the folding of short peptides

Using circular dichroism spectroscopy, we show evidence of unusual folding behaviour for several designed peptides in neat ionic liquid. Helical peptides, AKA(2) and Trp-cage, exhibit heat-induced folding, with stable helical structure persisting to 96 degrees C, whereas the beta-hairpin Trpzip4 is destabilized by the neat [C(4)mpy][Tf(2)N].