Protein Frameworks with Thiacalixarene and Zinc.

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 ( ), with its metal-binding capacity, affords the potential for simultaneous macrocycle- and metal-mediated protein assembly. Here, we describe the -/Zn-directed assembly of two proteins: cationic α-helical cytochrome (cyt ) and neutral β-propeller lectin (RSL). Two co-crystal forms were obtained with cyt , each involving multinuclear zinc sites supported by the cone conformation of . The /Zn cluster acted as an assembly node via both lysine encapsulation and metal-mediated protein-protein contacts. In the case of RSL, 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.