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Mechanism of protease inhibition in the protection of lungs against emphysema

Objective

Objectives:
The lungs are protected against enzymic damage by protease inhibitors, and principally by a1-antitrypsin. The overwhelming of these inhibitors as occurs in the genetic deficiency of a1-antitrypsin, gives cumulative destruction of lung elasticity with eventual development of emphysema. In order to pursue strategies for the prevention of this progression we need to understand the precise mechanism of protease inhibition. We now know the structure of a1-antitrypsin and can confidently deduce how the protease and inhibitor initially interact but the key step, the formation of the final irreversible complex, is still a matter of conjecture.

To determine the precise molecular mechanism involved we plan a combination of: 1) a crystallographic approach to give the structural relationships in the complex,
2) an NMR approach to show the bonding mechanism involved.

The lungs are protected against enzymic damage by protease inhibitors, and principally by alpha-1-antitrypsin. The overwhelming of these inhibitors as occurs in the genetic deficiency of alpha-1-antitrypsin, gives cumulative destruction of lung elasticity with eventual development of emphysema. In order to pursue strategies for the prevention of this progression we need to understand the precise mechanism of protease inhibition. We now know the structure of alpha 1-antitrypsin and can confidently deduce how the protease and inhibitor initially interact but the key step, the formation of the final irreversible complex, is still a matter of conjecture.

To determine the precise molecular mechanism involved we plan a combinationof:
1) a crystallographic approach to give the structural relationships in the complex;
2) an NMR approach to show the bonding mechanism involved.

To achieve this a series of recombinants of alpha-1-antitrypsin and proteases(trypsin and chymotrypsin) will be prepared with substitutions in the catalytic triad of the proteases and of the residues in alpha-1-antitrypsin modelled to interact with them. These recombinants together with other strategies make crystallisation of the complex feasible though not certain. The certain result will follow from 13C and 15N labelling of recombinants that will allow the characterisation of spatial and chemical distortion at the active/reactive sites by NMR. This will require the new technique of magic angle spinning NMR for which there is special expertise and facilities in Leiden. This application then is for support for a study bringing together experienced groups in the structure and function of alpha-1-antitrypsin from the UK, with the expertise in NMR available in the Netherlands. The overall aim is clear and achievable - to understand the mechanism by which alpha1-antitrypsin and other serpins formirreversible complexes with inflammatory proteases

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

THE CHANCELLOR, MASTERS AND SCHOLARS OF THE UNIVERSITY OF CAMBRIDGE
Address
Long Road
CB2 2PT Cambridge
United Kingdom

Participants (1)

LEIDEN UNIVERSITY
Netherlands
Address
55,Einsteinweg, 55 Gorlaeus Laboratories
2300 RA Leiden