Surface layers on bacteria

Surface layers on bacteria

Gram-negative bacteria are widespread, and can be harmful, causing antibiotic resistant infections, which are difficult to treat. Most bacteria have a protective surface layer made of proteins, termed S-layer. Although S-layer proteins are the most abundant class of proteins on earth, atomic resolution details of S-layers are not available. Therefore, the mechanisms of the assembly of S-layers in prokaryotes are poorly understood.

Andriko von Kügelgen from Tanmay Bharat’s lab together with colleagues, have successfully obtained a structure of the S-layer from the Gram-negative bacterium, Caulobacter crescentus, bound to the cell membrane via long sugars called lipopolysaccharides. By using a combination of electron cryo-microscopy, electron tomography, native mass spectrometry and molecular dynamics techniques, they have deduced the in-situ structure of lipopolysaccharide and the bound S-layer as it is found on cells. This study highlights the promising future of structural biology with atomic structure determination possible directly inside cells, with profound implications on structure-based drug design.

 

Heather Jeffery

von Kügelgen A, Tang H, Hardy GG, Kureisaite-Ciziene D, Brun YV, Stansfeld PJ, Robinson CV, Bharat TAM. (2019).

Cell 10.1016/j.cell.2019.12.006