Engineering protein assemblies with allosteric control via monomer fold-switching.
Campos, L.A., Sharma, R., Alvira, S., Ruiz, F.M., Ibarra-Molero, B., Sadqi, M., Alfonso, C., Rivas, G., Sanchez-Ruiz, J.M., Romero Garrido, A., Valpuesta, J.M., Munoz, V.(2019) Nat Commun 10: 5703-5703
- PubMed: 31836707 
- DOI: https://doi.org/10.1038/s41467-019-13686-1
- Primary Citation of Related Structures:  
6QIY, 6QIZ - PubMed Abstract: 
The macromolecular machines of life use allosteric control to self-assemble, dissociate and change shape in response to signals. Despite enormous interest, the design of nanoscale allosteric assemblies has proven tremendously challenging. Here we present a proof of concept of allosteric assembly in which an engineered fold switch on the protein monomer triggers or blocks assembly. Our design is based on the hyper-stable, naturally monomeric protein CI2, a paradigm of simple two-state folding, and the toroidal arrangement with 6-fold symmetry that it only adopts in crystalline form. We engineer CI2 to enable a switch between the native and an alternate, latent fold that self-assembles onto hexagonal toroidal particles by exposing a favorable inter-monomer interface. The assembly is controlled on demand via the competing effects of temperature and a designed short peptide. These findings unveil a remarkable potential for structural metamorphosis in proteins and demonstrate key principles for engineering protein-based nanomachinery.
Organizational Affiliation: 
Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Campus de Cantoblanco, 28049, Madrid, Spain.