Triggered reversible disassembly of an engineered protein nanocage

Abstract

Protein nanocages play crucial roles in sub-cellular compartmentalization and spatial control in all domains of life and have been used as biomolecular tools for applications in biocatalysis, drug delivery, and bionanotechnology. The ability to control their assembly state under physiological conditions would further expand their practical utility. To gain such control, we introduced a peptide capable of triggering conformational change at a key structural position in the largest known encapsulin nanocompartment. We report the structure of the resulting engineered nanocage and demonstrate its ability to on-demand disassemble and reassemble under physiological conditions. We demonstrate its capacity for in vivo encapsulation of proteins of choice while also demonstrating in vitro cargo loading capabilities. Our results represent a functionally robust addition to the nanocage toolbox and a novel approach for controlling protein nanocage disassembly and reassembly under mild conditions.

Exploring the Extreme Acid Tolerance of a Dynamic Protein Nanocage

“…4 Ongoing discoveries and research within the encapsulin field has resulted in the characterization of many nano-encapsulation systems with a quickly expanding and diverse list of useful molecular features. 10,11,14,18,28 However, relatively little attention has been focused on systematically exploring encapsulins from extremophilic bacteria and archaea with unusual molecular characteristics and stability profiles. With this study, we have taken the first step towards addressing this issue with a focus on the acid stability of the AaEnc nanocage.…”

“…2,4,10,11,17 The encapsulin shell in particular has received substantial attention in recent years. 17 Efforts aimed at increasing shell stability, 15 controlling shell assembly, 18 and modulating pore size and dynamics have recently been reported. 19,20 Encapsulin shells efficiently self-assemble under many conditions and display marked resistance against chemical or temperature denaturation, pH, and non-specific proteases.…”

The supramolecular chemistry of protein cages and viruses

“…In search of milder conditions for controlling encapsulin disassembly, Giessen and coworkers engineered the Quasibacillus thermotolerans encapsulin to include a pH-sensitive GALA peptide into the protein sequence. 31 This modified cage showed the ability to disassemble at pH 6 and reassemble at pH 7.5 in specific buffers, although there was some evidence of aggregation and an increase in average diameter that suggested the formation of partial defects in a minor proportion of cages.…”