Prokaryotes mostly lack membranous compartments that are typical of eukaryotic cells, but instead, they have various protein-based organelles. These include bacterial microcompartments like the carboxysome and the virus-like nanocompartment encapsulin. Encapsulins have an adaptable mechanism for enzyme packaging, which makes it an attractive platform to carry a foreign protein cargo. Here we investigate the assembly pathways and mechanical properties of the cargo-free and cargo-loaded nanocompartments, using a combination of native mass spectrometry, atomic force microscopy and multiscale computational molecular modeling. We show that encapsulin dimers assemble into rigid single-enzyme bacterial containers. Moreover, we demonstrate that cargo encapsulation has a mechanical impact on the shell. The structural similarity of encapsulins to virus capsids is reflected in their mechanical properties. With these robust mechanical properties encapsulins provide a suitable platform for the development of nanotechnological applications.
Snijder, J., Kononova, O., Barbu, I. M., Uetrecht, C., Rurup, W. F., Koay, M. S. T., ... Heck, A. J. R. (2016). Assembly and Mechanical Properties of the Cargo-Free and Cargo Loaded Bacterial Nanocompartment Encapsulin. Biomacromolecules, 17(8), 2522-2529. https://doi.org/10.1021/acs.biomac.6b00469