Five broad, long term goals of this laboratory are (i) to increase understanding of the molecular determinants of substrate specificity of (chymo) trypsin-like serine proteases, a large gene family that includes many medically important members and is among the most advanced model systems of enzymology, (ii) to develop powerful and robust techniques to distinguish the specificities of very closely related proteases, (iii) to facilitate the rational design of highly specific inhibitors of individual proteases, which can be used to examine the role of a particular protease in complex biological or pathological processes, (iv) to aid the de novo design of novel proteases with desired substrate specificities, and (v) to assist the development of novel therapeutic agents for the treatment of acute myocardial infarction and other thromboembolic disorders.
The specific aims of this renewal application are: 1 ) To elucidate optimal subsite occupancy for substrates of all three proteases of the human fibrinolytic cascade, tissue type plasminogen activator (t-PA), urokinase (u-PA), and plasmin, using both conventional and novel substrate phage display protocols. 2) To use site specific mutagenesis to identify and characterize molecular determinants of the stringent substrate specificities of t-PA and u-PA. 3) To design and characterize high affinity, specific inhibitors of u- PA. The proposed studies are interdisciplinary and involve the use of techniques of molecular biology (e.g., site directed mutagenesis, phage display), biochemistry (enzyme expression and purification, enzyme and inhibitor kinetics), biophysics (molecular modeling, X-ray crystallography), and chemistry (synthesis and characterization of small peptide substrates and peptidic inhibitors of serine proteases). The primary objective of this proposal, to increase understanding of the activity, specificity, and selective inhibition of fibrinolytic serine proteases, ensures that these studies will be directly relevant to human health. Administration of one of these enzymes (t-PA) is currently the standard treatment for acute myocardial infarction, the major killer of both American men and women. The development of novel plasminogen activators with altered or new properties, therefore, may provide improved thrombolytic agents. In addition, the development of high affinity, highly selective inhibitors of u-PA may provide new therapeutic tools to combat restenosis following invasive vascular procedures such as angioplasty.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL052475-08
Application #
6389365
Study Section
Hematology Subcommittee 2 (HEM)
Program Officer
Link, Rebecca P
Project Start
1994-08-01
Project End
2003-07-31
Budget Start
2001-08-01
Budget End
2002-07-31
Support Year
8
Fiscal Year
2001
Total Cost
$279,741
Indirect Cost
Name
Torrey Pines Institute for Molecular Studies
Department
Type
DUNS #
605758754
City
San Diego
State
CA
Country
United States
Zip Code
Beck, Z Q; Hervio, L; Dawson, P E et al. (2000) Identification of efficiently cleaved substrates for HIV-1 protease using a phage display library and use in inhibitor development. Virology 274:391-401
Hervio, L S; Coombs, G S; Bergstrom, R C et al. (2000) Negative selectivity and the evolution of protease cascades: the specificity of plasmin for peptide and protein substrates. Chem Biol 7:443-53
Coombs, G S; Rao, M S; Olson, A J et al. (1999) Revisiting catalysis by chymotrypsin family serine proteases using peptide substrates and inhibitors with unnatural main chains. J Biol Chem 274:24074-9
Zhang, Y L; Hervio, L; Strandberg, L et al. (1999) Distinct contributions of residue 192 to the specificity of coagulation and fibrinolytic serine proteases. J Biol Chem 274:7153-6
Coombs, G S; Bergstrom, R C; Madison, E L et al. (1998) Directing sequence-specific proteolysis to new targets. The influence of loop size and target sequence on selective proteolysis by tissue-type plasminogen activator and urokinase-type plasminogen activator. J Biol Chem 273:4323-8
Coombs, G S; Bergstrom, R C; Pellequer, J L et al. (1998) Substrate specificity of prostate-specific antigen (PSA). Chem Biol 5:475-88
Ke, S H; Coombs, G S; Tachias, K et al. (1997) Optimal subsite occupancy and design of a selective inhibitor of urokinase. J Biol Chem 272:20456-62
Tachias, K; Madison, E L (1997) Converting tissue type plasminogen activator into a zymogen. Important role of Lys156. J Biol Chem 272:28-31
Ke, S H; Tachias, K; Lamba, D et al. (1997) Identification of a hydrophobic exosite on tissue type plasminogen activator that modulates specificity for plasminogen. J Biol Chem 272:1811-6
Ke, S H; Coombs, G S; Tachias, K et al. (1997) Distinguishing the specificities of closely related proteases. Role of P3 in substrate and inhibitor discrimination between tissue-type plasminogen activator and urokinase. J Biol Chem 272:16603-9

Showing the most recent 10 out of 17 publications