Crystalline Cyclophane–Protein Cage Frameworks

Abstract

Cyclophanes are macrocyclic supramolecular hosts famous for their ability to bind atomic or molecular guests via noncovalent interactions within their well-defined cavities. In a similar way, porous crystalline networks, such as metal–organic frameworks, can create microenvironments that enable controlled guest binding in the solid state. Both types of materials often consist of synthetic components, and they have been developed within separate research fields. Moreover, the use of biomolecules as their structural units has remained elusive. Here, we have synthesized a library of organic cyclophanes and studied their electrostatic self-assembly with biological metal-binding protein cages (ferritins) into ordered structures. We show that cationic pillar[5]arenes and ferritin cages form biohybrid cocrystals with an open protein network structure. Our cyclophane–protein cage frameworks bridge the gap between molecular frameworks and colloidal nanoparticle crystals and combine the versatility of synthetic supramolecular hosts with the highly selective recognition properties of biomolecules. Such host–guest materials are interesting for porous material applications, including water remediation and heterogeneous catalysis.

Phthalocyanine–Virus Nanofibers as Heterogeneous Catalysts for Continuous‐Flow Photo‐Oxidation Processes

“…Importantly, strategies to control the interaction between the protein and the cocrystallization agent by means of pH and ionic strength of the aqueous media has enabled fine tuning in the kinetics of the assembly process, leading to high structural control. Recent examples of protein crystal scaffolds with catalytic activity indicate that biohybrids can function as efficient catalysts . While protein cages such as (apo)ferritin or cowpea chlorotic mottle virus have coped the most recent developments in 3D electrostatic assemblies, other protein scaffolds such as tobacco mosaic virus (TMV) have been recently explored, yielding unidimensional morphologies …”

Highly ordered protein cage assemblies: A toolkit for new materials

“…Apoferritin (aFt) Electrostatic Au nanoparticles (AuNP) Kostiainen et al (2013) Polypeptides Bellapadrona et al (2015); Korpi et al (2018) Dendrons and dendrimers Liljeström, Seitsonen, & Kostiainen (2015); Välimäki et al (2015) Protein Künzle, Eckert, and Beck (2016); Lach, Künzle, and Beck (2017) Small cyclic molecules Beyeh et al (2018) Organic dye Mikkilä et al (2016) Ce 3+ Okuda, Suzumoto, and Yamashita (2011)…”

“…Many hollow scaffolds can be filled with magnetic particles to introduce magnetic responses in addition to the protein properties initially Korpi et al (2018). Copyright 2018 American Chemical Society, Beyeh et al (2018). Copyright 2018 American Chemical Society, Mikkilä et al (2016).…”

Multi‐Component Self‐Assembly of Proteins and Inorganic Particles: From Discrete Structures to Biomimetic Materials

“…In a similar approach, native protein containers were co-assembled with dendrimer molecules, organic dyes or supramolecular hosts such as cyclophanes. [36] Several multi-component lattice types were obtained using native protein containers.…”