Matthias Wilmanns

The molecular function of the virulence factor YopP from Yersinia

Principle Investigator:

Dr. Matthias Wilmanns, EMBL-Hamburg

Background:
The protein YopP/YopJ from the gram-negative bacterIa Yersinia presents a key virulence factor of this pathogenic organism (Mukherjee et al, 2007). YopP/YopJ, originally thought to act as a bacterial protein with protease activity, has been characterized as an acetyltransferase, modifying serine or threonine residues from several members of the human mitogen-activated protein kinase superfamily. Acetylation interferes with several associated signaling cascades, thus contributing to Yersinia induced infection. YopP/YopJ from Yersinia is a 32 kDa protein. Despite the importance of this virulence factor, however, a detailed characterization of the molecular mechanism of host kinase acetylation by YopP/YopJ has not been carried out, to date. The aim of this project is to unravel the molecular mechanism of this peculiar type of pathogen-mediated host protein-modification. We are intending to address the following questions:

  1. What is the molecular structure of YopP/YopJ? What kind of domain-domain arrangement is involved in the overall architecture? What is the structure of the active site?
  2. What is the molecular mechanism of YopP/YopJ enzymatic activity? What kind of reaction intermediates are involved? What are the relations to established enzymatic mechanisms?
  3.  Are the mechanistic findings supported by in vitro (cell cultures) and in vivo assays (animal models)?

To approach these questions, we are planning to apply the following methods and technologies:
YopP/YopJ will be expressed and purified to allow its crystallization and X-ray structure determination. The focus will be on the full-length protein, in the presence or absence of reaction substrates. There will be also a particular interest to crystallize the enzyme acyl-enzyme intermediate (Mukherjee et al, 2006). The work will be carried out at EMBL-Hamburg. In addition, the central LEXI protein production facility, EMBL core facilities and facilities from the EC-PCUBE project (http://www.p-cube.eu/) will be offered to the project.

References:
Mukherjee S, Hao YH, Orth K (2007) A newly discovered post-translational modification--the acetylation of serine and threonine residues. Trends Biochem Sci 32(5): 210-216
Mukherjee S, Keitany G, Li Y, Wang Y, Ball HL, Goldsmith EJ, Orth K (2006) Yersinia YopJ acetylates and inhibits kinase activation by blocking phosphorylation. Science 312(5777): 1211-1214

Homepage of the Wilmanns Group
http://www.embl-hamburg.de/research/unit/wilmanns/

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