Search Organism: All OrganismsArabidopsis thalianaBacillus subtilis 168Bos taurusCaenorhabditis elegansCanis familiarisDanio rerioDrosophila melanogasterEquus caballusEscherichia coli K12Gallus gallusHomo sapiensMacaca mulattaMus musculusNematostella vectensisOryza sativaPan troglodytesRattus norvegicusSaccharomyces cerevisiaeSchizosaccharomyces pombeStrongylocentrotus purpuratusTakifugu rubripesXenopus laevis home help / support contribute downloads mirrors about us Proc. Natl. Acad. Sci. U.S.A. May (1990); 87(9):3530-3 Amino acid residues that affect interaction of tissue-type plasminogen activator with plasminogen activator inhibitor 1. Madison EL, Goldsmith EJ, Gerard RD, Gething MJ, Sambrook JF, Bassel-Duby RS Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235. Abstract: Fibrinolysis is regulated in part by the interaction between tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor 1 (PAI-1, a serine protease inhibitor of the serpin family). It is known from our earlier work that deletion of a loop of amino acids (residues 296-302) from the serine protease domain of t-PA suppresses the interaction between the two proteins without altering the reactivity of t-PA towards its substrate, plasminogen. To define more precisely the role of individual residues within this loop, we have used site-directed mutagenesis to replace Lys-296, Arg-298, and Arg-299 with negatively charged glutamic residues. Replacement of all three positively charged amino acids generates a variant of t-PA that associates inefficiently with PAI-1 and is highly resistant to inhibition by the serpin. Two t-PAs with point mutations (Arg-298----Glu and Arg-299----Glu) are partially resistant to inhibition by PAI-1 and associate with the serpin at intermediate rates. Other point mutations (Lys-296----Glu, His-297----Glu, and Pro-301----Gly) do not detectably affect the interaction of t-PA with PAI-1. None of these substitutions has a significant effect on the rate of catalysis by t-PA or on the affinity of the enzyme for its substrate, plasminogen. On the basis of these results, we propose a model in which positively charged residues located in a surface loop near the active site of t-PA form ionic bonds with complementary negatively charged residues C-terminal to the reactive center of PAI-1. [PUBMED: 2110366] Copyright © 2009, Tyers Lab, The Samuel Lunenfeld Research Institute, Mount Sinai Hospital, All Rights Reserved. terms and conditions - privacy policy - Osprey Network Visualization System BioGRID: A General Repository for Interaction Datasets. Chris Stark, Bobby-Joe Breitkreutz, Teresa Reguly, Lorrie Boucher, Ashton Breitkreutz, Mike Tyers. Nucleic Acids Res. Jan 1;34:D535-9.