|Eva M. Egelseer, Christine Völlenkle, Magdalena Pleschberger, Dieter Moll, Nicola Ilk, Carina Huber, Andreas Breitwieser, Uwe B. Sleytr, and Margit Sára
Center for Ultrastructure Research, Ludwig-Boltzmann-Institute for Molecular Nanotechnology, University of Agricultural Sciences, Gregor-Mendel-Str. 33, A-1180 Vienna, Austria
Many bacteria and archaea possess crystalline bacterial cell surface layers (S-layers) as their outermost cell envelope component which show either oblique, square, or hexagonal lattice symmetry. In bacteria, the S-layer subunits are linked to each other and to the underlying cell envelope layer by non covalent interactions and recognize a distinct type of secondary cell wall polymer (SCWP) as the proper anchoring structure in the rigid cell wall layer. Particularly the recrystallization of recombinant S-layer fusion proteins on any type of support coated with the appropriate SCWP should allow the functionalization of surfaces with a porous protein lattice while maintaining the biological properties of the fused peptide. The genes encoding the S-layer proteins SbsA and SbsB of Geobacillus stearothermophilus PV72, SbsC of G. stearothermophilus ATCC 12980 and SbpA of Bacillus sphaericus CCM 2177 have been sequenced and cloned. Based on these S-layer proteins, different S-layer fusion proteins were constructed, carrying either streptavidin, the major birch pollen allergen Bet v1, the hypervariable region of a camel antibody or the Fc-binding domain as the biologically active sequence.