The Self-Assembly of Catechol Functionalized a/b-Peptide Foldamers

Abstract

Peptide foldamers consisted of homogeneous trans-ACPC backbone self-assemble into well-defined 3D architectures (foldectures) with unique morphologies such as windmill, square rod and molar tooth. To diversify the foldectures, there have been efforts to modify the peptide backbone by introducing different amino acids. Recently, heterogeneous backbones of \alpha/\beta-peptide foldamers have been used as building blocks for self-assembly to produce intriguing morphologies such as parallelogram plate and truncated bipyramids. Although a variety of interesting morphologies have been self-assembled with potential to mimic biological structures, applications for foldectures are limited to this date.

To further diversify foldectures and expand the scope for applications, employing functional groups with well-known and specific functions to the foldamer backbone seems like an interesting proposition.

In this study, 1,4-dihydroxylphenylalanine (L-DOPA) was employed within the \alpha/\beta- peptide foldamer building block to add functionality to the self-assembled structure. Upon self-assembly, the resulting foldecture displayed rod shapes. To induce cross-linking between the catechol moieties incorporated within the structures, sodium periodate was added to the foldectures. Upon mechanical stirring, the structures were physically intact. Also, the functionalized foldamers were self-assembled in the presence of sodium periodate to investigate the degree of cross-linking. Lastly, the DOPA functionalized foldamers were exposed to sodium periodate to investigate the cross-linking ability of the catechol units. These results may be useful in the intramolecular and intermolecular cross-linking of foldectures.