MEMPROT · Structural studies of membrane proteases
FP6 — Marie Curie Actions (Human Resources and Mobility)
- Duration
- 2006-11-01 → 2010-10-31
- EU contribution
- €27,582,802
- Participants
- 3
- Scheme
- TOK
Lines connect the coordinator with its partners. CORDIS does not always give exact coordinates for projects before 2014. These points are placed at city or country level.
Results in brief
Final Activity Report Summary - MEMPROT (Structural studies of membrane proteases.)
Membrane proteins play essential roles in life: they act as ion channels, ion pumps, signalling centres, proteases, light harvesters in plants, and as the producers of the cellular energy currency ATP in mitochondria. Despite their central importance in all kingdoms of life, and the interest in human membrane proteins as drug targets (up to 50% of all marketed drugs target membrane proteins), the structural and mechanistic understanding of membrane proteins lacks far behind the understanding of their soluble counterparts. This is due to difficulties at all stages in the work with membrane proteins: membrane proteins are more difficult to produce than soluble proteins, require expensive detergents for membrane extraction and purification, and tend to crystallise poorly. In this project, we have attempted to purify membrane proteins, and particularly membrane proteases, both from natural sources and from genetically modified expression cells. So far, we have been able to grow crystals of one membrane protein complex, the photosystem II from the tobacco plant. This work is described in the publication "Crystallisation of the Photosystem II core complex and its chlorophyll binding subunit CP43 from transplastomic plants of Nicotiana tabacum. Piano D, El Alaoui S, Korza HJ, Filipek R, Sabala I, Haniewicz P, Buechel C, De Sanctis D, Bochtler M., Photosynth Res. 2010 Nov 10, epub ahead of print", which is attached to this report. Crystallisation of the other membrane embedded proteases that we have been able to express is still on-going.
Data: CORDIS, © European Union
Project objective
Proteases are key players in many cellular processes and come in great variety. There are essentially five different catalytic types: serine/threonine, cysteine, aspartic and metallopeptidases. Each type of active site can be found in several different folds, which suggests that active sites have been reinvented multiple times during evolution. The soluble peptidase folds have been studied in great detail, and in nearly all cases, at least one prototype crystal structure is available. In contrast, there are almost no crystal structures of integral membrane proteases, therefore their mechanistic understanding lies far behind. It is not even clear whether a specific water channel is required to transport a catalytic water molecule to the active site or whether a low concentration of water in the lipid bilayer is sufficient for amide cleavage. Despite these uncertainties, the combined results of sequence comparisons and biochemical studies suggest that membrane and soluble proteases will probably turn out to have (a) dissimilar folds and (b) similar active sites. However, there is no good evidence yet for a membrane-embedded cysteine peptidase, and for several membrane protease families the assignment of the catalytic type is controversial, which may be an indication for a novel type of active site. In order to broaden the spectrum of our research we are planning to acquire new skills in membrane protein overexpression, purification and crystallization which we would then apply for structural studies of membrane proteases.
Original text from CORDIS.
Participants
- INTERNATIONAL INSTITUTE OF MOLECULAR AND CELL BIOLOGY · WARSAWCoordinatorCity levelPoland
- DIAMOND LIGHT SOURCE · OXFORDSHIREUnited Kingdom
- STOCKHOLM UNIVERSITY · STOCKHOLMCity levelSweden
Links
Data: CORDIS, © European Union