Continuous, Topologically Guided Protein Crystallization Controls Bacterial Surface Layer Self-Assembly
- Bacteria assemble the cell envelope using localized enzymes to account for growth and division of a topologically complicated surface. However, a regulatory pathway has not been identified for assembly and maintenance of the surface layer (S-layer), a 2D crystalline protein coat surrounding the curved 3D surface of a variety of bacteria. By specifically labeling, imaging, and tracking native and purified RsaA, the S-layer protein (SLP) from C. crescentus, we show that protein self-assembly alone is sufficient to assemble and maintain the S-layer in vivo. By monitoring the location of newly produced S-layer on the surface of living bacteria, we find that S-layer assembly occurs independently of the site of RsaA secretion and that localized production of new cell wall surface area alone is insufficient to explain S-layer assembly patterns. When the cell surface is devoid of a pre-existing S-layer, the location of S-layer assembly depends on the nucleation characteristics of SLP crystals, which grow by capturing RsaA molecules freely diffusing on the outer bacterial surface. Based on these observations, we propose a model of S-layer assembly whereby RsaA monomers are secreted randomly and diffuse on the lipopolysaccharide (LPS) outer membrane until incorporated into growing 2D S-layer crystals. The complicated topology of the cell surface enables formation of defects, gaps, and grain boundaries within the S-layer lattice, thereby guiding the location of S-layer assembly without enzymatic assistance. This unsupervised mechanism poses unique challenges and advantages for designing treatments targeting cell surface structures or utilizing S-layers as self-assembling macromolecular nanomaterials. As an evolutionary driver, 2D protein self-assembly rationalizes the exceptional S-layer subunit sequence and species diversity.
|Type of resource
|March 23, 2017 - April 1, 2019
|Nomellini, John F.
- Use and reproduction
- User agrees that, where applicable, content will not be used to identify or to otherwise infringe the privacy or confidentiality rights of individuals. Content distributed via the Stanford Digital Repository may be subject to additional license and use restrictions applied by the depositor.
- This work is licensed under a Creative Commons Attribution Non Commercial No Derivatives 3.0 Unported license (CC BY-NC-ND).
- Preferred Citation
- Comerci, Colin and Herrmann, Jonathan et al. (2019) Continuous, Topologically Guided Protein Crystallization Controls Bacterial Surface Layer Self-Assembly. Stanford Digital Repository. Available at: https://purl.stanford.edu/xq476jv8407
Stanford Research DataView other items in this collection in SearchWorks
Also listed in
Loading usage metrics...