Self-assembly and recrystallization of bacterial S-layer proteins at silicon supports imaged in real time by atomic force microscopy.
The self-assembly of bacterial surface-layer (S-layer) proteins (SbpA of Bacillus sphaericus CCM 2177) at silicon supports (hydrophobic, non-plasma-treated and hydrophilic, O2 plasma-treated silicon supports) was imaged in real time by atomic force microscopy (AFM). A closed mosaic layer consisting of small crystals (less than 200 nm in diameter) was formed at a hydrophobic silicon support, whereas a coherent crystalline lattice consisting of large domains (2-10 micro m in size) was generated at O2 plasma-treated, hydrophilic silicon wafers. The structure of the formed layers was a monolayer (9 nm in height) at the hydrophobic silicon and a bilayer (15 nm in height) at the hydrophilic silicon. In situ AFM measurements confirmed the importance of ionic bonds in the formation of crystalline SbpA layers at silicon supports. Rupture of the protein subunits with a metal chelator from the crystalline lattice of SbpA was visualized in situ by AFM. The stability of solid-supported SbpA layers could be enhanced by cross-linking the S-layers with amino-amino or amino-carboxyl group directed cross-linkers.
Györvary
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Center for Ultrastructure Research and Ludwig Bolzmann Institute for Molecular Nanotechnology, Universität für Bodenkultur Wien, Gregor-Mendel Strasse 33, A-1180 Vienna, Austria. gyoervary@ima-mst.at
Stein
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Pum
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Sleytr
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UB
D001407:Bacillus / Q000254:growth & development / Q000378:metabolism*; D001426:Bacterial Proteins; D003460:Crystallization; D018625:Microscopy, Atomic Force / Q000379:methods*; D009004:Monosaccharide Transport Proteins / Q000737:chemistry* / Q000378:metabolism*; D012825:Silicon
D001426:Bacterial Proteins; D009004:Monosaccharide Transport Proteins; C120455:SbpA protein, bacteria; D012825:Silicon