Reprogramming an ATP-Driven Biological Machine into a Light-Gated Protein Nanocage

Abstract

Supramolecular protein assemblies are attractive materials for engineering nanoscale machines with controllable functions. Protein monomers have been engineered to self-assemble into symmetrical complexes, metal-templated structures and cage-like architectures. The mechanistic complexity of protein machines, however, has made it difficult to engineer assemblies with not only new architectures but also desired functions. Here we describe an approach to controlling functional states of a protein assembly with light. The approach uses covalently attached molecular spacers that reversibly switch interatomic distances upon illumination. We applied this strategy to convert an ATP-dependent homo-oligomeric group II chaperonin to a light-driven machine that undergoes large-scale conformational changes between open and closed states visualized by single particle cryo-electron microscopy. The resulting light-gated nanocontainer can capture and release non-native cargos. The design principle of alternately stabilizing conformational states by switching atomic distances illuminates the cooperativity of evolved protein assemblies and provides a strategy for engineering other light-controlled biologically inspired machines.View Large Image | View Hi-Res Image | Download PowerPoint Slide