Abstract
Controlled protein assembly provides a means to generate biomaterials. Synthetic macrocycles such as the water-soluble sulfonato-calix[n]arenes are useful mediators of protein assembly. Sulfonato-thiacalix[4]arene (tsclx4), with its metal-binding capacity, affords the potential for simultaneous macrocycle- and metal-mediated protein assembly. Here, we describe the tsclx4-/Zn-directed assembly of two proteins: cationic α-helical cytochrome c (cyt c) and neutral β-propeller Ralstonia solanacearum lectin (RSL). Two co-crystal forms were obtained with cyt c, each involving multinuclear zinc sites supported by the cone conformation of tsclx4. The tsclx4/Zn cluster acted as an assembly node via both lysine encapsulation and metal-mediated protein–protein contacts. In the case of RSL, tsclx4 adopted the 1,2-alternate conformation and supported a dinuclear zinc site with concomitant encapsulation and metal-binding of two histidine side chains. These results, together with the knowledge of thiacalixarene/metal nanoclusters, suggest promising applications for thiacalixarenes in biomaterials and MOF fabrication.
Highlights
This paper describes the application of macrocycle-metal complexes to protein assembly, as evidenced by crystallography
In each of the model systems, incorporation of the macrocycle−metal complexes contributed to protein assembly and crystal packing. These results suggest that tsclx4/Zn complexes are an additional tool for protein assembly, with applications in peptide-/protein-based metal organic framework (MOF).[1,2,4,7]
Two crystal forms with distinct morphologies occurred in the presence of zinc
Summary
This paper describes the application of macrocycle-metal complexes to protein assembly, as evidenced by crystallography. Zinc has a strong propensity to act as a bridging ion at (crystal) packing interfaces. These properties can be utilized for engineered protein assembly by the inclusion of designed metal sites. Mutant forms of the normally monomeric cytochrome cb[562] spontaneously assembled into two- or three-dimensional crystalline arrays in the presence of zinc.[1,3] the combination of bivalent hydroxamate-containing ligands with a mutant ferritin bearing zinc binding sites yielded a protein-based metal organic framework (MOF).[4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
