S-layer

An S-layer (surface layer) is a part of the cell envelope found in almost all archaea, as well as in many types of bacteria.[1][2] The S-layers of both archaea and bacteria consists of a monomolecular layer composed of only one (or, in a few cases, two) identical proteins or glycoproteins.[3] This structure is built via self-assembly and encloses the whole cell surface. Thus, the S-layer protein can represent up to 15% of the whole protein content of a cell.[4] S-layer proteins are poorly conserved or not conserved at all, and can differ markedly even between related species. Depending on species, the S-layers have a thickness between 5 and 25 nm and possess identical pores 2–8 nm in diameter.[5]

The terminology “S-layer” was used the first time in 1976.[6] The general use was accepted at the "First International Workshop on Crystalline Bacterial Cell Surface Layers, Vienna (Austria)" in 1984, and in the year 1987 S-layers were defined at the European Molecular Biology Organization Workshop on “Crystalline Bacterial Cell Surface Layers”, Vienna as “Two-dimensional arrays of proteinaceous subunits forming surface layers on prokaryotic cells” (see "Preface", page VI in Sleytr "et al. 1988"[7]). For a brief summary on the history of S-layer research see "References". [2][8]

  1. ^ Albers SV, Meyer BH (2011). "The archaeal cell envelope". Nature Reviews Microbiology. 9 (6): 414–426. doi:10.1038/nrmicro2576. PMID 21572458. S2CID 10297797.
  2. ^ a b Sleytr UB, Schuster B, Egelseer EM, Pum D (2014). "S-layers: Principles and Applications". FEMS Microbiology Reviews. 38 (5): 823–864. doi:10.1111/1574-6976.12063. PMC 4232325. PMID 24483139.
  3. ^ Rodrigues-Oliveira, Thiago; Belmok, Aline; Vasconcellos, Deborah; Schuster, Bernhard; Kyaw, Cynthia M. (2017-12-22). "Archaeal S-Layers: Overview and Current State of the Art". Frontiers in Microbiology. 8: 2597. doi:10.3389/fmicb.2017.02597. ISSN 1664-302X. PMC 5744192. PMID 29312266.
  4. ^ Sleytr U, Messner P, Pum D, Sára M (1993). "Crystalline bacterial cell surface layers". Mol. Microbiol. 10 (5): 911–6. doi:10.1111/j.1365-2958.1993.tb00962.x. PMID 7934867. S2CID 86119414.
  5. ^ Sleytr U, Bayley H, Sára M, Breitwieser A, Küpcü S, Mader C, Weigert S, Unger F, Messner P, Jahn-Schmid B, Schuster B, Pum D, Douglas K, Clark N, Moore J, Winningham T, Levy S, Frithsen I, Pankovc J, Beale P, Gillis H, Choutov D, Martin K (1997). "Applications of S-layers". FEMS Microbiol. Rev. 20 (1–2): 151–75. doi:10.1016/S0168-6445(97)00044-2. PMID 9276930.
  6. ^ Sleytr UB (1976). "Self-assembly of the hexagonally and tetragonally arranged subunits of bacterial surface layers and their reattachment to cell walls". J. Ultrastruct. Res. 55 (3): 360–367. doi:10.1016/S0022-5320(76)80093-7. PMID 6800.
  7. ^ Sleytr UB, Messner P, Pum D, Sára M (1988). Sleytr UB, Messner P, Pum D, Sára M (eds.). Crystalline Bacterial Cell Surface Layers. Berlin: Springer. doi:10.1007/978-3-642-73537-0. ISBN 978-3-540-19082-0. S2CID 20244135.
  8. ^ Sleytr UB (2016). Curiosity and Passion for Science and Art. Series in Structural Biology. Vol. 7. Singapore: World Scientific Publishing. doi:10.1142/10084. ISBN 978-981-3141-81-0.