Chirality of Superhelices Self-Assembled from Polypeptide Mixtures

Superhelices with tunable chirality have been constructed; however, the formation mechanism of superhelical chirality is complicated, especially for assembly systems containing multiple chiral components. Revealing the contributions of each chiral component to superhelical chirality remains a challenge. Herein, we report that mixtures of polypeptide homopolymers and block copolymers can coassemble into superhelices, in which the homopolymers aggregate into bundlelike templates, and the block copolymers wrap on the templates to form helical screws. It was found that the chirality of the superhelices formed by polypeptide mixtures can be regulated by the chiralities of homopolymers and copolymers. The effects of initial solvent composition, temperature, and polypeptide chirality were examined systematically. Interestingly, for the mixtures containing block copolymers and homopolymers with opposite chirality, only left-handed or righthanded superhelices can be formed, and the superhelical chirality cannot be inverted. Based on experimental observations, a mechanism that can well explain the origin of superhelical chirality was proposed. This work deepens the understanding of superhelix chirality and provides guidance for the construction of hierarchical nanostructures with controllable chirality.

Automated summary

The study reveals that mixtures of polypeptide homopolymers and block copolymers can form superhelices with tunable chirality. The chirality of the superhelices can be regulated by the chiralities of the homopolymers and copolymers. A mechanism explaining the origin of superhelical chirality is proposed based on experimental observations. This work deepens the understanding of superhelix chirality and provides guidance for the construction of hierarchical nanostructures with controllable chirality.