Investigation of bacterial survival strategies in metalliferous environments: Molecular biological studies on S-layer proteins

Generally, heavy metal contamination of the environment is a result of either natural events like volcanic emissions or human activities such as mining processes. High concentrations of heavy metals are toxic to the majority of organisms. However, several bacteria exhibit surprising strategies to survive in metalliferous environments. These strategies are attractive for novel bio-based resource technologies. Their understanding is the purpose of our research.

Lysinibacillus sphaericus JG-B53, an isolate from the uranium mining waste pile Haberland, was studied using genome sequencing analyses in order to identify strain intrinsic survival strategies like surface (S) layer proteins with metal specific binding affinities and metal specific transporter proteins. Using the Next generation sequencing technology and bioinformatic analyses of the whole genome sequence of L. sphaericus JG-B53 with the Genomics Workbench (CLC bio) we identified 15 putative S-layer protein genes and 3 metal ion exporter protein genes for metals that occur in the natural habitat of Lysinibacillus sphaericus JG-B53. Their characteristics were analysed with multiple gene and protein analyzing programs. The protein expression was analyzed using cDNA analyses (Lederer, 2012; Lederer et al, 2013) .
Future studies will analyse recombinant S-layer proteins regarding their lattice symmetry and metal binding affinities.

References:

Lederer FL 2012. Genetic characterization, heterologous expression and application of S-layer proteins from the bacterial isolates Lysinibacillus sphaericus JG-B53 and Lysinibacillus sphaericus JG-A12. PhD Thesis, University of Rostock.
Lederer FL, Weinert U, Günther T, Raff J, Pollmann K. 2013. Identification of survival strategies of Lysinibacillus sphaericus JG-B53 in heavy metal and radionuclide contaminated soil. In preparation.