| Abstract
| - The only molecules that are currently known to fold into unique three-dimensional conformationsand perform sophisticated functions are biological polymers − proteins and some RNA molecules. Ouraim is to create a nonbiological sequence-specific polymer that folds in aqueous solution. Toward thatend, we synthesized sequence-specific 30mer, 45mer, and 60mer peptoid oligomers (N-substituted glycinepolymers) consisting of 15mer units we chained together by disulfide and oxime linkages to mimic thehelical bundle structures commonly found in proteins. Because these 15mer sequences were previouslyshown to form defined helical structures that aggregate together at submillimolar concentrations, we expectedthat by covalently linking multiple 15mers together, they might fold as helical bundles. To probe whetherthey folded, we used fluorescence resonance energy transfer (FRET) reporter groups. We found that certainconstructs fold up with a hydrophobic core and have cooperative folding transitions. Such molecules mayultimately provide a platform for designing specific functions resembling those of proteins.
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