Research project P4/03 (Research action P4)
Protein engineering, theoretical chemistry and organic synthesis are utilized to analyse some fundamental biological phenomena : enzymatic catalysis, protein folding and interactions between macromolecules in cell division, signal transmission and interactions between pro- and eukaryotic cells. An excellent complementarity exists between the network participants. Molecular biology, protein chemistry, enzymology, theoretical chemistry and crystallography (ULg), organic synthesis (UCL/CHOR), protein sequencing, mass spectrometry and crystallography (RUG), analysis of transmembrane peptides and of surface properties of proteins (FUSAGx), molecular biology and interactions between cells (UCL/ICP). Some overlapping results in a higher degree of specialization and a better coordination between the teams.
The main research themes are the following :
1.Enzymatic catalysis : study of penicillin-recognizing proteins. A first group of enzymes, DD-peptidases, are the targets of beta -lactam antibiotic. They lie on the outer face of the bacterial cytoplasmic membrane. They are active-site serine peptidases responsible for essential steps in the biosynthesis of the bacterial cell wall. By contrast, beta -lactamases efficiently hydrolyse the same antibiotics and belong to two distinct families : active-site serine and Zn++ enzymes.
2.Protein folding. Serine and Zn2+ beta-lactamases were chosen as models. With the former, the behaviour of catalytic covalent intermediates and, with the latter, the role of the metal ion will receive particular attention.
3.Complex molecular machineries. Interactions between Yersinia enterocolitica and macrophages, induction of beta -lactamase synthesis and the protein complexes forming the divisome in Escherichia coli and Enterococcus hirae will be studied. Many of these proteins are membrane-bound and are responsible for signal transmission and/or cell-cell interactions.
4.Theoretical chemistry. The behaviour of "soft" atoms, which can absorb bond deformation during chemical reactions is analysed at the quantum chemistry level. The energetic and geometric aspects are detailed in direct connection with the synthesis of new potential ligands, inactivators or substrates.
5.Organic chemistry : design of new potential Penicilium Binding Protein (PBP) and beta-lactamase inhibitors ; development of new methods for synthesizing these structures.
6.Practical applications of this project include
- the design of better antibiotics which might inactivate DD-peptidases while escaping the action of beta-lactamases;
- a better understanding of the infection pathway ofYersinia, which should result in the design of new weapons against this pathogen and others sharing the " type III " secretion pathway;
- a better understanding of the rules governing the stability of proteins which might be extrapolated to proteins of industrial interest.
