and Specific Aims.) Inhibitors of proteolytic enzymes have multiple roles in limiting the molecular and cellular mechanisms of inflammation, which if not controlled, would result in acute and chronic lung damage. Specifically, human neutrophil elastase (HNE), and other neutrophil proteases, are controlled by plasma proteins belonging to the serine protease inhibitor (serpin) family of proteins. Inactivated or kinetically overwhelmed serpins result in unregulated proteolytic activity which often has severe and life-threatening consequences. The proposed experiments focus on the molecular biology, structural biology and biochemistry of human serpins and serine proteases in order to define the molecular interactions between these two species. Given the central role of HNE in the pathophysiology of a wide variety of lung diseases, this enzyme was chosen as the model target protease, for these studies.
The Specific Aims are to determine the mechanism and structural basis of: 1) the one-to-one stoichiometry of inhibition between a serpin and HNE; 2) the rate constant of inhibition of HNE; and 3) the long-term stability of the serpin-HNE complex. The investigations proposed will utilize the high resolution crystal structure of an intact, active recombinant variant of antichymotrypsin which is an inhibitor of HNE, cathepsin G and chymotrypsin and a general kinetic scheme of serpin/enzyme reactions to guide the design and analysis of specific recombinant serpins. The three dimensional structure and biochemical properties of the newly created series of serpins will be analyzed in order to devise a structure/function algorithm that will provide a foundation on which to base a more complete understanding of the molecular properties of the serpins.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL050523-02
Application #
2226750
Study Section
Lung Biology and Pathology Study Section (LBPA)
Project Start
1994-05-01
Project End
1999-04-30
Budget Start
1995-05-01
Budget End
1996-04-30
Support Year
2
Fiscal Year
1995
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Schechter, Norman M; Plotnick, Michael I (2004) Measurement of the kinetic parameters mediating protease-serpin inhibition. Methods 32:159-68
Plotnick, Michael I; Samakur, Madhurika; Wang, Zhi Mei et al. (2002) Heterogeneity in serpin-protease complexes as demonstrated by differences in the mechanism of complex breakdown. Biochemistry 41:334-42
Que, Xuchu; Brinen, Linda S; Perkins, Penny et al. (2002) Cysteine proteinases from distinct cellular compartments are recruited to phagocytic vesicles by Entamoeba histolytica. Mol Biochem Parasitol 119:23-32
Plotnick, Michael I; Rubin, Harvey; Schechter, Norman M (2002) The effects of reactive site location on the inhibitory properties of the serpin alpha(1)-antichymotrypsin. J Biol Chem 277:29927-35
Estebanez-Perpina, E; Fuentes-Prior, P; Belorgey, D et al. (2000) Crystal structure of the caspase activator human granzyme B, a proteinase highly specific for an Asp-P1 residue. Biol Chem 381:1203-14
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Janciauskiene, S; Rubin, H; Lukacs, C M et al. (1998) Alzheimer's peptide Abeta1-42 binds to two beta-sheets of alpha1-antichymotrypsin and transforms it from inhibitor to substrate. J Biol Chem 273:28360-4
Wang, Z; Walter, M; Selwood, T et al. (1998) Recombinant expression of human mast cell proteases chymase and tryptase. Biol Chem 379:167-74
O'Malley, K M; Nair, S A; Rubin, H et al. (1997) The kinetic mechanism of serpin-proteinase complex formation. An intermediate between the michaelis complex and the inhibited complex. J Biol Chem 272:5354-9
Plotnick, M I; Schechter, N M; Wang, Z M et al. (1997) Role of the P6-P3' region of the serpin reactive loop in the formation and breakdown of the inhibitory complex. Biochemistry 36:14601-8

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