S-layer proteins

Potential Application in Nanobiotechnology

The beginning of Biotechnology

S-layer Proteins

• Challenges of Biotechnology:– Nano structured surfaces– Self assembled structures in the few to tens of

nanometers– Problematic to graft with Lithographic techniques– Too big for classical chemical synthesis– Microorganisms to synthesis structures

S-layer Proteins

• Aim of Applied Molecular engineering

– Design of self assembling nanostructures

• DNA• Proteins• Lipids

DNA self assembly

DNA Origami

DNA Origami

S-layer Proteins

• DNA based functional Nanostructures:

– 2D lattices– 3D cages– Networks of DNA structures interfaced with

proteins, e.g. Streptavidin

S-layer Proteins

• Protein based functional nanostructures:– proteins as patterning elements– Self assembling fusion proteins to form 2D and 3D

structures

As an alternative to engineered and designed fusion proteins that self assemble into larger patterns is to exploit naturally self assembling proteins into crystalline patterns

S-layer Proteins

• The cell surface envelope proteins (S-layer proteins) (Sleytr et al., 1999)

• S-layer proteins are the outermost component of the cell envelope

• They represent a universal feature of archea.• E.g. Haloferax Volcanii has its surface covered

to 98 % with S-layer proteins• Gram positive bacteria such as Micrococcus

lysodeicticus contains S-layer proteins

S-layer Proteins

• S-layer lattices are composed in most cases of a single protein or glycoprotein species,that self assemble into

• Oblique• Hexagonal• Square• symmetry

S-layer proteins

S-layer Proteins

S-layer Proteins

Electron Micrograph of a gram positive bacterium with a square p4 S-layer lattice

S-layer Proteins

S-layer proteins

S-layer Proteins

• S-layer proteins are a first order self assembly system that has been optimised during the course of evolution.

• In bacteria the S-layer proteins are linked to each other and the underlying cell envelope by

• Non covalent forces• These proteins can maintain their self

assembly potential even after isolation.

S-layer Proteins

S-layer Proteins

S-layer Proteins

S-layer Proteins

S-layer Proteins

• The s-layer cyrstal lattices as found on the outside of bacterial cells can be restored on

• Synthetic substrates such as.• Silicon wafers• Noble metal surfaces• Langmuir lipid films• Liposomes• plastics

S-layer proteins

S-layer assembly in Solution

Crystal growth at interfaces

S-layer growth on Si surfaces

S-layer Proteins

Patterning of S-layers on Si surfaces

S-layer Proteins

S-layer Proteins patterning by soft lithography

S-layer Proteins

S-layer Proteins

S-layer Proteins

S-layer Proteins

S-layer Proteins

S-layer Proteins

S-layer Proteins

S-layer Proteins

S-layer Proteins

S-layer Proteins

S-layer Proteins

S-layer Proteins Biomimetic cell membranes

S-layer Proteins: Biomimetic lipid membrane

S-layer supported lipid membranes

S-layer Proteins

S-layer Proteins