Metal‐Templated Design of Chemically Switchable Protein Assemblies with High‐Affinity Coordination Sites
Albert Kakkis, Derek M. Gagnon, Julian Esselborn, R. David Britt, F. Akif Tezcan
Abstract
Abstract To mimic a hypothetical pathway for protein evolution, we previously tailored a monomeric protein (cyt cb 5 62 ) for metal‐mediated self‐assembly, followed by re‐design of the resulting oligomers for enhanced stability and metal‐based functions. We show that a single hydrophobic mutation on the cyt cb 562 surface drastically alters the outcome of metal‐directed oligomerization to yield a new trimeric architecture, (TriCyt1) 3. This nascent trimer was redesigned into second and third‐generation variants (TriCyt2) 3 and (TriCyt3) 3 with increased structural stability and preorganization for metal coordination. The three TriCyt variants combined furnish a unique platform to 1) provide tunable coupling between protein quaternary structure and metal coordination, 2) enable the construction of metal/pH‐switchable protein oligomerization motifs, and 3) generate a robust metal coordination site that can coordinate all mid‐to‐late first‐row transition‐metal ions with high affinity.