Nanoscale structures and materials from the self-assembly of polypeptides and DNA

: The use of biological molecules with programmable self-assembly properties is an attractive route to functional nanomaterials. Proteins and peptides have been used extensively for these systems due to their biological relevance and large number of supramolecular motifs, but it is still difficult to build highly anisotropic and programmable nanostructures due to their high complexity. Oligonucleotides, by contrast, have the advantage of programmability and reliable assembly, but lack biological and chemical diversity. In this review, we discuss systems that merge protein or peptide self-assembly with the addressability of DNA. We outline the various self-assembly motifs used, the chemistry for linking polypeptides with DNA, and the resulting nanostructures that can be formed by the interplay of these two molecules. Finally, we close by suggesting some interesting future directions in hybrid polypeptide-DNA nanomaterials, and potential applications for these exciting hybrids.

Structure–property relations in linear viscoelasticity of supramolecular hydrogels

A model is developed for the linear viscoelastic response of supramolecular gels and applied to the analysis of structure–property relations in gels with various supramolecular motifs.

Facilitating functionalization of benzene-1,3,5-tricarboxamides by switching amide connectivity

Selective functionalization of C3-symmetrical supramolecular motifs was achieved by switching the amide connectivity of one side chain, yielding supramolecular polymers with a tunable number of functional groups.

Solvent influence on the crystal packing of 6-aminothiocytosine

The crystal structures of 6-aminothiocytosine (systematic name: 4,6-diamino-1,2-dihydropyrimidine-2-thione, DAPMT, C4H6N4S), its hemihydrate (0.5H2O) and its dimethylformamide (DMF, C3H7NO) monosolvate were compared, and the influence of the type of solvent on the supramolecular motifs was analysed. In all three crystal structures, there are two symmetry-independent molecules (A and B), and these molecules are connected by three relatively short and directional hydrogen bonds to form chains of alternating A and B molecules. A further organization of these chains is dependent on the nature of the solvent molecule. In the unsolvated form, two orientations of the neighbouring chains are observed, and similar motifs – but only one per structure – can be observed in the solvated structures. These two different motifs can be connected by two different kinds of contacts, i.e. either π–π (hemihydrate) or staple-supported S...S (DMF). In the crystal structures, the O atoms of the solvent molecules are double acceptors of the same type of hydrogen bonds and bind the chains of DAPMT molecules into different motifs (dimeric or infinite chains). A Hirshfeld fingerprint analysis was used for visualization and additional interpretation of these results.

Sequence-defined l-glutamamide oligomers with pendant supramolecular motifs via iterative synthesis and orthogonal post-functionalization

One of the great challenges in polymer chemistry is to achieve discrete and sequence-defined synthetic polymers that fold in defined conformations and form well-defined three-dimensional structured particles.