Daniel J. Muller, Wolfgang Baumeister, and Andreas Engel Conformational Change of the Hexagonally Packed Intermediate Layer of Deinococcus radiodurans Monitored by Atomic Force Microscopy Daniel J. Muller, Wolfgang Baumeister, and Andreas Engel Presented by Robert Warden

Bacterial Surface Layers Protein layer surrounds cells Usually a single protein Self-assemble into regular patterns Hydrophobic/hydrophilic sides Involved in transport two and from cell D. radiodurans S-Layer Hexagonal 6-mer Well-characterized structurally and biochemically

Atomic Force Microscopy Protein in native environment Different cantilevers Hydrophilic – Si3N4 Hydrophobic – Carbon Forces of <0.2 nN Study dynamic processes

AFM Images Consistent with previous studies Images of inner surface (hydrophobic)

Dynamic Studies Spontaneous open/closed shift Not effected by change of cantilever Open to Closed 5 min Closed to Open

Significance AFM can be done in native environment Dynamic Information Forces too small to disrupt structure Proteins can be adsorbed to surface Dynamic Information

Questions?