The Plasticity of Molecular Interactions Governs Bacterial Microcompartment Shell Assembly

Structure. 2019 May 7;27(5):749-763.e4. doi: 10.1016/j.str.2019.01.017. Epub 2019 Mar 1.


Bacterial microcompartments (BMCs) are composed of an enzymatic core encapsulated by a selectively permeable protein shell that enhances catalytic efficiency. Many pathogenic bacteria derive competitive advantages from their BMC-based catabolism, implicating BMCs as drug targets. BMC shells are of interest for bioengineering due to their diverse and selective permeability properties and because they self-assemble. A complete understanding of shell composition and organization is a prerequisite for biotechnological applications. Here, we report the cryoelectron microscopy structure of a BMC shell at 3.0-Å resolution, using an image-processing strategy that allowed us to determine the previously uncharacterized structural details of the interactions formed by the BMC-TS and BMC-TD shell subunits in the context of the assembled shell. We found unexpected structural plasticity among these interactions, resulting in distinct shell populations assembled from varying numbers of the BMC-TS and BMC-TD subunits. We discuss the implications of these findings on shell assembly and function.

Keywords: bacterial microcompartments; bioengineering; cryoelectron microscopy; metabolosome; microbiology; modular assembly; permeability; structural biology.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Algorithms
  • Bacterial Proteins / chemistry*
  • Cryoelectron Microscopy
  • Ligands
  • Metabolome
  • Myxococcales / chemistry*
  • Organelles / chemistry
  • Permeability
  • Protein Multimerization
  • Protein Structure, Secondary
  • Software


  • Bacterial Proteins
  • Ligands

Supplementary concepts

  • Haliangium ochraceum