Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

1 Publication

Bacterial S-layer proteins and their interaction with radionuclides

Raff, J.; Vogel, M.; Drobot, B.; Schmoock, C.; Moll, H.; Barkleit, A.; Börnick, H.; Worch, E.; Stumpf, T.


Bacterial surface-layer (S-layer) proteins form the outermost cell envelope of many bacteria and all archaea. These proteins are able to self-assemble in highly regular layers forming an oblique, square or hexagonal lattice on the entire cell. This layer protects especially bacteria living in extreme habitats against diverse harmful environmental influences. In case of uranium mining waste pile isolates belonging to the genera Lysinibacillus and Bacillus it was proven that the S-layers act as scavenger for reactive oxygen species probably formed by either radiolysis of water or Fenton reaction. The inactivation of the radicals is achieved by intermolecular crosslinking of tyrosine residues of the protein monomers. Furthermore, these S-layers have a variety of free functional groups such as carboxyl, hydroxyl and amino groups determined by potentiometric titration. These groups form at least two different calcium binding sites being important for the self-assembly of the protein and are responsible for the selective binding of toxic elements. Additionally, S-layer proteins are posttranslationally modified with sugar residues, phosphate, sulfate or sulfoxide groups. While hexavalent uranium is bound by several surface exposed functional groups, it is easily released at acidic pH and thusly do not affect strongly cell metabolism. However, the trivalent curium substitutes calcium and is only released at pH 2.0 or below. Interestingly, metabolism relevant metals such as Mn, Fe, Co, Ni, Cu, Zn were not bound by the proteins. These examples demonstrate that radionuclides can specifically interact with the biosphere affecting significantly their behaviour even in natural environments.

Keywords: Radionuclides; S-layer

Involved research facilities

Related publications

  • Invited lecture (Conferences)
    Frontiers in Environmental Radioactivity, 06.-07.01.2016, London, United Kingdom


Years: 2023 2022 2021 2020 2019 2018 2017 2016 2015