Di-Gluebodies as covalently-rigidified, modular protein assemblies enable simultaneous determination of high-resolution, low-size, cryo-EM structures

Abstract

Cryo-EM has become a routine structural biology method, yet elucidation of small proteins (<100 kDa) and increasing throughput remain challenging. Here, we describe covalently-dimerized engineered nanobodies, Di-Gluebodies, as novel and modular imaging scaffolds to address the challenges. They can simultaneously display two copies of the same protein or two distinct proteins, providing sufficient rigidity required by cryo-EM. We validate this method with multiple soluble and membrane targets, demonstrating that this provides a flexible and scalable platform for expanded protein structure determination.