A Supramolecular Assembly of Hemoproteins Formed in a Star-Shaped Structure via Heme-Heme Pocket Interactions

Preparation of Cage-Like Micellar Assemblies of Engineered Hemoproteins

Natural protein assemblies have encouraged scientists to create large supramolecular systems consisting of various protein motifs. In the case of hemoproteins containing heme as a cofactor, several approaches have been reported to form artificial assemblies with various structures such as fibers, sheets, networks, and cages. This chapter describes the design, preparation, and characterization of cage-like micellar assemblies for chemically modified hemoproteins including hydrophilic protein units attached to hydrophobic molecules. Detailed procedures are described for constructing specific systems using cytochrome b562 and hexameric tyrosine-coordinated heme protein as hemoprotein units with heme-azobenzene conjugate and poly-N-isopropylacrylamide as attached molecules.

Artificial protein assemblies with well-defined supramolecular protein nanostructures

Nature uses a wide range of well-defined biomolecular assemblies in diverse cellular processes, where proteins are major building blocks for these supramolecular assemblies. Inspired by their natural counterparts, artificial protein-based assemblies have attracted strong interest as new bio-nanostructures, and strategies to construct ordered protein assemblies have been rapidly expanding. In this review, we provide an overview of very recent studies in the field of artificial protein assemblies, with the particular aim of introducing major assembly methods and unique features of these assemblies. Computational de novo designs were used to build various assemblies with artificial protein building blocks, which are unrelated to natural proteins. Small chemical ligands and metal ions have also been extensively used for strong and bio-orthogonal protein linking. Here, in addition to protein assemblies with well-defined sizes, protein oligomeric and array structures with rather undefined sizes (but with definite repeat protein assembly units) also will be discussed in the context of well-defined protein nanostructures. Lastly, we will introduce multiple examples showing how protein assemblies can be effectively used in various fields such as therapeutics and vaccine development. We believe that structures and functions of artificial protein assemblies will be continuously evolved, particularly according to specific application goals.