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New Approaches in the Crystallisation and Crystallography of Membrane Proteins

Objective



Membrane proteins perform a staggering range of blological functions. Structural research on membrane proteins is, however, only a partially conquered area; only 6 independent structures of integral membrane proteins have been reported so far. A more fundamental understanding of the structure-function relationships in membrane proteins requires the development of new techniques and methodologies, and would make invaluable contributions to structural biology, physiology and medicine. It is extremely difficult to purify and crystallise membrane proteins. Even if the proteln can be crystallised, there follows usually a set of other problems ln structure solution, mainly due to the often very low quality of these crystals. A breakthrough in the crystallography of membrane proteins requires new approaches in protein purification, crystallisation and data collection. Our main objectives are to develop these new techniques. We intend to undertake 3-dimensional structural studies on a wide range of integral membrane proteins and to perform dynamic structural studies on these systems to gain new insights into their mechanism. Inter-Europe collaboration with laboratories who have already achieved large scale preparation and crystallisation of membrane proteins plays an essential part in the project. We propose to start with respiratory membrane proteins, where we have already obtained high quality crystals. Development of new techniques will proceed in parallel with these studies. The new techniques will then be applied to new membrane protein systems.
TASK 1: Structural studies of respiratory membrane proteins.
(1) High resolution and kinetic crystallography on respiratory oxidases (2) Structural analysis of cytochrome bcl complex
(3) Structural studies on complex I and related enzymes
TASK 2: Development of new techniques in membrane protein crystallography.
(1) Development of new purification techniques for membrane proteins (2) Development of new crystallisation techniques for membrane proteins (3) Development of an efficient data collection system
TASK 3: Application of the newly developed techniques to other systems (1) Multi-drug resistance transporters
(2) Bacterial pilus usher proteins
(3) Membrane proteins in potassium transport and osmoregulation
TASK 4: Education, training and technology transfer
While each sub-project is an important and integrated component of the proposal the individual projects also have significant scientific, commercial and pharmaceutical values. The development of new purification techniques will affect a very wide area of protein research. The planed X-ray data collection system for membrane proteins will be immediately applicable to many other supramolecular structures like viruses and ribosomes.
The planned structural studies of respiratory membrane protei.ns will give substantial contributions to bioenergetics. It is anticipated that once the crystallisation and structural analysis of the potassium transporters and the multidrug resistance transporters are achieved, drug design and targeting will form the basis of separate proposals to the EU, in conjunction with pharmaceutic companies.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

UPPSALA UNIVERSITY
Address
3,Husargatan 3
751 23 Uppsala
Sweden

Participants (1)

Institute of Enzymology, Biological Research Centre - Hungarian Academy of Sciences
Hungary
Address
29,Karolin Ut 29
1113 Budapest