In situ structure of an intact lipopolysaccharide-bound bacterial surface layer

Journal article

Most bacterial and all archaeal cells are encapsulated by a paracrystalline, protective, and cell-shape-determining proteinaceous surface layer (S-layer). On Gram-negative bacteria, S-layers are anchored to cells via lipopolysaccharide. Here, we report an electron cryomicroscopy structure of the Caulobacter crescentus S-layer bound to the O-antigen of lipopolysaccharide. Using native mass spectrometry and molecular dynamics simulations, we deduce the length of the O-antigen on cells and show how lipopolysaccharide binding and S-layer assembly is regulated by calcium. Finally, we present a near-atomic resolution in situ structure of the complete S-layer using cellular electron cryotomography, showing S-layer arrangement at the tip of the O-antigen. A complete atomic structure of the S-layer shows the power of cellular tomography for in situ structural biology and sheds light on a very abundant class of self-assembling molecules with important roles in prokaryotic physiology with marked potential for synthetic biology and surface-display applications.

Authors: Von Kügelgen, A; Tang, H; Hardy, GG; Kureisaite-Ciziene, D; Brun, YV

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Cell
• Volume: 180
• Issue: 2
• Pages: 348-358
• Publication date: 2019-12-26
• Acceptance date: 2019-12-04
• DOI: 10.1016/j.cell.2019.12.006
• EISSN: 1097-4172
• ISSN: 0092-8674
• Language: English
• Keywords: FFR