Visualization of Bacterial Microcompartment Facet Assembly Using High-Speed Atomic Force Microscopy
Markus Sutter†‡, Matthew Faulkner§, Clément Aussignargues†, Bradley C. Paasch†, Steve Barrett∥, Cheryl A. Kerfeld*†‡⊥#∇, and Lu-Ning Liu*§
† MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States
‡ Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
§Institute of Integrative Biology and ∥Department of Physics, University of Liverpool, Liverpool L69 7ZB, United Kingdom
⊥ Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California 94720, United States
# Berkeley Synthetic Biology Institute, Berkeley, California 94720, United States
∇ Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
Nano Lett., Article ASAP
Publication Date (Web): November 30, 2015
Copyright © 2015 American Chemical Society
*(L.-N.L.) E-mail: Luning.Liu@liverpool.ac.uk., *(C.K.) E-mail: ckerfeld@lbl.gov.
ACS AuthorChoice - This is an open access article published under a Creative Commons Attribution (CC-BY)License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited.
Abstract
Bacterial microcompartments (BMCs) are proteinaceous organelles widespread among bacterial phyla. They compartmentalize enzymes within a selectively permeable shell and play important roles in CO2 fixation, pathogenesis, and microbial ecology. Here, we combine X-ray crystallography and high-speed atomic force microscopy to characterize, at molecular resolution, the structure and dynamics of BMC shell facet assembly. Our results show that preformed hexamers assemble into uniformly oriented shell layers, a single hexamer thick. We also observe the dynamic process of shell facet assembly. Shell hexamers can dissociate from and incorporate into assembled sheets, indicating a flexible intermolecular interaction. Furthermore, we demonstrate that the self-assembly and dynamics of shell proteins are governed by specific contacts at the interfaces of shell proteins. Our study provides novel insights into the formation, interactions, and dynamics of BMC shell facets, which are essential for the design and engineering of self-assembled biological nanoreactors and scaffolds based on BMC architectures.
Keywords: Bacterial microcompartment; high-speed atomic force microscopy; protein dynamics; protein interaction; self-assembly
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