Researchers Decipher the Structure of a Bacterial Microcompartment

Understanding assembly principles may inspire new approaches for making valuable products.

Click to enlarge photo. Enlarge Photo

Structural model of a bacterial microcompartment. Different proteins are represented by the gold and green patches on the blue surface.

The Science

Unlike higher forms of life, bacteria do not possess internal “organs,” or organelles. This means that certain vital enzymatic reactions can’t be sequestered from the rest of cell. However, some bacteria possess highly organized structures that compartmentalize reactions. These structures are known as bacterial microcompartments (BMCs). Instead of having an organelle’s outer membrane, however, BMCs are surrounded by an outside “shell.” The shell is made of different modular protein building blocks. A team of scientists has, for the first time, provided a clear picture of how these modular components fit together to form a BMC shell. They also showed the pores let selected molecules enter and exit.

The Impact

These results provide a structural basis to better understand how molecules cross the BMC shell via the pores, what biophysical processes guide the self-assembly of the shell, and how specific enzymes end up inside of the BMC while others do not. Understanding how BMCs assemble and function may eventually enable scientists to design and engineer BMCs with improved functions. For example, BMCs could be designed for carbon dioxide fixation or photosynthetic efficiency. The shells could also be created for novel purposes such as producing specialty chemicals.

Contact

Cheryl A. Kerfeld
Michigan State University
Lawrence Berkeley National Laboratory
Ckerfeld@lbl.gov

Funding

This research was supported by the National Institutes of Health, National Institute of Allergy and Infectious Diseases and the Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences. The Advanced Light Source (ALS) is supported by the DOE, Director, Office of Science, Office of Basic Energy Sciences. B.G. was supported by an advanced postdoctoral mobility fellowship from the Swiss National Science Foundation. The Stanford Synchrotron Radiation Lightsource (SSRL), SLAC National Accelerator Laboratory, is supported by the DOE, Office of Science, Office of Basic Energy Sciences. The SSRL resources used are supported, in part, by the DOE, Office of Science, Office of Biological and Environmental Research.  Both the ALS and SSRL are DOE Office of Science scientific user facilities.

Publications

M. Sutter, B. Greber, C. Aussignargues, and C.A. Kerfeld, “Assembly principles and structure of a 6.5-MDa bacterial microcomponent shellExternal link.” Science 356 (6344), 1293 (2017). [DOI: 10.1126/science.aan3289]

Related Links

Michigan State University-Department of Energy Plant Research Laboratory news article: Our first ever look at a bacterial organelle shellsExternal link

Stanford Synchrotron Radiation Lightsource: Structural molecular biologyExternal link

Highlight Categories

Program: BES, CSGB, SUF, BER, BSSD

Performer/Facility: University, DOE Laboratory, SC User Facilities, BES User Facilities, ALS, SSRL

Additional: Collaborations, Non-DOE Interagency Collaboration

Last modified: 12/7/2020 1:09:06 PM