LAUSR

Many bacteria use protein‐based organelles known as bacterial microcompartments (BMCs) to organize and sequester sequential enzymatic reactions. Regardless of their specialized metabolic function, all BMCs are delimited by a shell made of multiple structurally redundant, yet functionally diverse, hexameric (BMC‐H), pseudohexameric/trimeric (BMC‐T), or pentameric (BMC‐P) shell protein paralogs. When expressed without their native cargo, shell proteins have been shown to self‐assemble into 2D sheets, open‐ended nanotubes, and closed shells of ≈40 nm diameter that are being developed as scaffolds and nanocontainers for applications in biotechnology. Here, by leveraging a strategy for affinity‐based purification, it is demonstrated that a wide range of empty synthetic shells, many differing in end‐cap structures, can be derived from a glycyl radical enzyme‐associated microcompartment. The range of pleomorphic shells observed, which span ≈2 orders of magnitude in size from ≈25 nm to ≈1.8 µm, reveal the remarkable plasticity of BMC‐based biomaterials. In addition, new capped nanotube and nanocone morphologies are observed that are consistent with a multicomponent geometric model in which architectural principles are shared among asymmetric carbon, viral protein, and BMC‐based structures.