Abstract
Proteins are versatile natural building blocks with highly complex and multifunctional architectures, and self-assembled protein structures have been created by the introduction of covalent, noncovalent, or metal-coordination bonding. Here, we report the robust, selective, and reversible metal coordination properties of unnatural chelating amino acids as the sufficient and dominant driving force for diverse protein self-assembly. Bipyridine-alanine is genetically incorporated into a D3 homohexamer. Depending on the position of the unnatural amino acid, 1-directional, crystalline and noncrystalline 2-directional, combinatory, and hierarchical architectures are effectively created upon the addition of metal ions. The length and shape of the structures is tunable by altering conditions related to thermodynamics and kinetics of metal-coordination and subsequent reactions. The crystalline 1-directional and 2-directional biomaterials retain their native enzymatic activities with increased thermal stability, suggesting that introducing chelating ligands provides a specific chemical basis to synthesize diverse protein-based functional materials while retaining their native structures and functions.
Highlights
Proteins are versatile natural building blocks with highly complex and multifunctional architectures, and self-assembled protein structures have been created by the introduction of covalent, noncovalent, or metal-coordination bonding
The polymerization driven by metal coordination to chelating ligands is explored with protein building blocks of which the sequence is neither optimized nor templated for self-assembly
The thermodynamic parameters of the first-row transition metal ions such as log KOH−, log K1, and log K2 for bpy ligands have been obtained from the literature[40,41] (Supplementary Table 1 and Supplementary Note 1)
Summary
Proteins are versatile natural building blocks with highly complex and multifunctional architectures, and self-assembled protein structures have been created by the introduction of covalent, noncovalent, or metal-coordination bonding. Metal-coordination either to surface-exposed natural amino acids such as histidine and glutamate or to chemically modified amino acids[30,31,32,33,34,35] endows strong driving force for self-assembly, while often requiring sequence optimization to create selective metal-binding sites[30,32]. While these methods have enabled the formation of numerous protein-assemblies, alternative and orthogonal approaches that are less dependent on the identity of the building blocks may expand the scope and diversity of the protein architectures. Thermodynamic and kinetic controls associated with inorganic reactivity are applied to investigate whether the shape and length of the protein-assembled architectures can be tunable
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
