Designer Nanorings with Functional Cavities from Self-Assembling beta-Sheet Peptides

Abstract

beta-Barrel proteins that take the shape of a ring are common in many types of water-soluble enzymes and water-insoluble transmembrane pore-forming proteins. Since beta-barrel proteins perform diverse functions in the cell, it would be a great step towards developing artificial proteins if we can control the polarity of artificial beta-barrel proteins at will. Here, we describe a rational approach to construct beta-barrel protein mimics from the self-assembly of peptide-based building blocks. With this approach, the direction of the self-assembly process toward the formation of water-soluble beta-barrel nanorings or water-insoluble transmembrane beta-barrel pores could be controlled by the simple but versatile molecular manipulation of supramolecular building blocks. This study not only delineates the basic driving force that underlies the folding of beta-barrel proteins, but also lays the foundation for the facile fabrication of beta-barrel protein mimics, which can be developed as nanoreactors, ion-and small-molecule-selective pores, and novel antibiotics.