Type III secretion system chaperones and effectors
We are working on several components, effectors and chaperones of the Y. enterocolotica type III and enteropathogenic Escherichia coli (EPEC) secretion systems. For efficient secretion, type III secretion system effectors require specific chaperone proteins that keep the effectors in a partially unfolded state prior to transfer through the injectisome.
After having solved the structure of the YopT chaperone SycT (Büttner et al, 2005) we recently solved the structure of SycD, which is responsible for translocator proteins showing a tetratricopeptide repeat fold (Heinz, 2007, in press) .
EPEC exploits the human adapter protein Nck as part of its infection strategy. During infection Nck specifically recognizes the phosphorylated translocated intimin receptor (Tir) which is inserted into the host membrane and eventually leads to dynamic bacteria-presenting protrusions of the plasma membrane known as pedestals. Using surface plasmon resonance spectroscopy, peptide epitope scanning and crystal structure determination of the Nck1 and Nck2 SH2-domains in complex with Tir-derived phosphopeptides we were able to investigate and differentiate the phosphopeptide binding affinities of Nck1 and Nck2 (Frese et al., 2006).
- Structure and Function of Proteins - Prof. Wulf Blankenfeldt