Biogenesis and functions of bacterial S-layers

  title={Biogenesis and functions of bacterial S-layers},
  author={Robert P. Fagan and Neil F. Fairweather},
  journal={Nature Reviews Microbiology},
The outer surface of many archaea and bacteria is coated with a proteinaceous surface layer (known as an S-layer), which is formed by the self-assembly of monomeric proteins into a regularly spaced, two-dimensional array. Bacteria possess dedicated pathways for the secretion and anchoring of the S-layer to the cell wall, and some Gram-positive species have large S-layer-associated gene families. S-layers have important roles in growth and survival, and their many functions include the… 

S-layer Structure in Bacteria and Archaea

This chapter covers the structural aspects of SLPs and S-layer assembly, which provide the basis for a wide range of applications in biotechnology and nanobiology.

S-layers: The Proteinaceous Multifunctional Armors of Gram-Positive Pathogens

This mini-review revisits the sequence-structure-function relationships of S-layers, SLPs, and SLAPs in Gram-positive pathogens, focusing on the best-studied classes, Bacilli (Bacillus anthracis) and Clostridia (Clostridioides difficile).

Spatial organization of Clostridium difficile S-layer biogenesis

It is concluded that this delocalized secretion of SlpA leads to a pool of precursor in the cell wall which is available to repair openings in the S-layer formed during cell growth or following damage.

Structure and assembly of the S-layer in C. difficile

The crystal structure of SlpA, the main S-layer protein of the bacterial pathogen Clostridioides difficile, is reported and it is shown that a mutant lacking this region becomes susceptible to lysozyme, an important molecule in host defence.

Structure and assembly of the S-layer determine virulence in C. difficile

This work combines X-ray and electron crystallography to reveal a novel S-layer organization in atomic detail, highlighting the need for multiple technical approaches to obtain structural information on these paracrystalline arrays and establishing a direct link between specific structural elements of S- layer and virulence for the first time.

Reassembly of S-layer proteins

This review examines the intrinsic capability of isolated native and recombinant S-layer proteins to form self-assembled mono- or double layers in suspension, at solid supports, the air-water interface, planar lipid films, liposomes, nanocapsules, and nanoparticles.

Molecular Logic of Prokaryotic Surface Layer Structures

Structure of the hexagonal surface layer on Caulobacter crescentus cells

This study spans different spatial scales from atoms to cells by combining X-ray crystallography with electron cryotomography and sub-nanometre-resolution sub-tomogram averaging and results in a pseudo-atomic-level description of the in vivo S-layer, which agrees completely with the atomicX-ray lattice model.

Deletion of S-Layer Associated Ig-Like Domain Protein Disrupts the Lactobacillus acidophilus Cell Surface

Identification of similar proteins in alternative bacterial species may help pinpoint next-generation host-adapted probiotic candidates.

Two Outer Membrane Proteins Contribute to Caulobacter crescentus Cellular Fitness by Preventing Intracellular S-Layer Protein Accumulation

This study demonstrates that Caulobacter crescentus has two homologous outer membrane transporter proteins that are involved in S-layer export, and provides new insight into the requirement for RsaFa and RsaFb in cellular fitness and tolerance to antimicrobial agents.



S-Layer Anchoring and Localization of an S-Layer-Associated Protease in Caulobacter crescentus

The S-layer of the gram-negative bacterium Caulobacter crescentus is composed of a single protein, RsaA, that is secreted and assembled into a hexagonal crystalline array that covers the organism, which led to the discovery that Sap was an extracellular membrane-bound protease, rather than intracellular, as previously proposed.

Functions of S-layers.

The following review up-dates the functional basis of S-layers and describes such diverse topics as the effect of S -layers on the Gram stain, bacteriophage adsorption in lactobacilli, phagocytosis by human polymorphonuclear leukocytes, the adhesion of a high-molecular-mass amylase, outer membrane porosity, and the secretion of extracellular enzymes of Thermoanaerobacterium.

Structure of the surface layer of the methanogenic archaean Methanosarcina acetivorans

The results provide insight into the evolutionary origins of primitive cell envelope structures, of which the S-layer is considered to be among the most primitive: it also provides a platform for the development of self-assembling nanomaterials with diverse functional and structural properties.

The S-Layer Glycome—Adding to the Sugar Coat of Bacteria

X-ray crystallography experiments allowed first insights into the catalysis mechanism of selected enzymes, and it will be exciting to fully exploit the S-layer glycome for glycoengineering purposes and to link it to the bacterial interactome.

Archaeal surface layer proteins contain beta propeller, PKD, and beta helix domains and are related to metazoan cell surface proteins.

Three domain types that account for the complete architecture of numerous Methanosarcina surface layer proteins (SLPs) are identified and the crystal structure for two of these domains are solved, suggesting remarkable relationships between domains in archaeal SLPs and metazoan cell surface proteins.

Surface-Layer (S-Layer) Proteins Sap and EA1 Govern the Binding of the S-Layer-Associated Protein BslO at the Cell Septa of Bacillus anthracis

It is proposed that the dynamic Sap/EA1 S-layer coverage of the envelope restricts the deposition of BslO to the secondary cell wall polysaccharide (SCWP) at septal rings.