Leucine 42 in the fibronectin motif of streptokinase plays a critical role in fibrin-independent plasminogen activation

Lin Liu, Irina Yurievna Sazonova, Ryan B. Turner, Shakeel A. Chowdhry, Judy Tsai, Aiilyan K. Houng, Guy L. Reed

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

The NH2 terminus (residues 1-59) of streptokinase (SK) is a molecular switch that permits fibrin-independent plasminogen activation. Targeted mutations were made in recombinant (r) SK1-59 to identify structural interactions required for this process. Mutagenesis established the functional roles of Phe-37and Glu-39, which were projected to interact with microplasmin in the activator complex. Mutation of Leu-42 (rSK1-59(L42A)), a conserved residue in the SK fibronectin motif that lacks interactions with microplasmin, strongly reduced plasminogen activation (k(cat) decreased 50-fold) but not arnidolysis (k(cat) decreased 1.5-fold). Otherwise rSK1-59(L42A) and native rSK1-59 were indistinguishable in several parameters. Both displayed saturable and specific binding to Glu-plasminogen or the remaining SK fragment (rSKA59). Similarly rSK1-59 and rSK1-59(L42A) bound simultaneously to two different plasminogen molecules, indicating that both plasminogen binding sites were intact. However, when bound to SKΔ59, rSK1-59(L42A) was less effective than rSK1-59 in restructuring the native conformation of the SK A domain, as detected by conformation-dependent monoclonal antibodies. In the light of previous studies, these data provide evidence that SK1-59 contributes to fibrin-independent plasminogen activation through 1) intermolecular inter-actions with the plasmin in the activator complex, 2) binding interactions with the plasminogen substrate, and 3) intramolecular interactions that structure the A domain of SK for Pg substrate processing.

Original languageEnglish (US)
Pages (from-to)37686-37691
Number of pages6
JournalJournal of Biological Chemistry
Volume275
Issue number48
DOIs
StatePublished - Dec 1 2000

Fingerprint

Streptokinase
Plasminogen
Fibrin
Fibronectins
Leucine
Chemical activation
Conformations
Mutagenesis
Mutation
Fibrinolysin
Substrates
Binding Sites
Monoclonal Antibodies
Switches
Molecules
Processing

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Liu, L., Sazonova, I. Y., Turner, R. B., Chowdhry, S. A., Tsai, J., Houng, A. K., & Reed, G. L. (2000). Leucine 42 in the fibronectin motif of streptokinase plays a critical role in fibrin-independent plasminogen activation. Journal of Biological Chemistry, 275(48), 37686-37691. https://doi.org/10.1074/jbc.M003963200

Leucine 42 in the fibronectin motif of streptokinase plays a critical role in fibrin-independent plasminogen activation. / Liu, Lin; Sazonova, Irina Yurievna; Turner, Ryan B.; Chowdhry, Shakeel A.; Tsai, Judy; Houng, Aiilyan K.; Reed, Guy L.

In: Journal of Biological Chemistry, Vol. 275, No. 48, 01.12.2000, p. 37686-37691.

Research output: Contribution to journalArticle

Liu, Lin ; Sazonova, Irina Yurievna ; Turner, Ryan B. ; Chowdhry, Shakeel A. ; Tsai, Judy ; Houng, Aiilyan K. ; Reed, Guy L. / Leucine 42 in the fibronectin motif of streptokinase plays a critical role in fibrin-independent plasminogen activation. In: Journal of Biological Chemistry. 2000 ; Vol. 275, No. 48. pp. 37686-37691.
@article{f243bbc927b542dd8333939e71c5a0a8,
title = "Leucine 42 in the fibronectin motif of streptokinase plays a critical role in fibrin-independent plasminogen activation",
abstract = "The NH2 terminus (residues 1-59) of streptokinase (SK) is a molecular switch that permits fibrin-independent plasminogen activation. Targeted mutations were made in recombinant (r) SK1-59 to identify structural interactions required for this process. Mutagenesis established the functional roles of Phe-37and Glu-39, which were projected to interact with microplasmin in the activator complex. Mutation of Leu-42 (rSK1-59(L42A)), a conserved residue in the SK fibronectin motif that lacks interactions with microplasmin, strongly reduced plasminogen activation (k(cat) decreased 50-fold) but not arnidolysis (k(cat) decreased 1.5-fold). Otherwise rSK1-59(L42A) and native rSK1-59 were indistinguishable in several parameters. Both displayed saturable and specific binding to Glu-plasminogen or the remaining SK fragment (rSKA59). Similarly rSK1-59 and rSK1-59(L42A) bound simultaneously to two different plasminogen molecules, indicating that both plasminogen binding sites were intact. However, when bound to SKΔ59, rSK1-59(L42A) was less effective than rSK1-59 in restructuring the native conformation of the SK A domain, as detected by conformation-dependent monoclonal antibodies. In the light of previous studies, these data provide evidence that SK1-59 contributes to fibrin-independent plasminogen activation through 1) intermolecular inter-actions with the plasmin in the activator complex, 2) binding interactions with the plasminogen substrate, and 3) intramolecular interactions that structure the A domain of SK for Pg substrate processing.",
author = "Lin Liu and Sazonova, {Irina Yurievna} and Turner, {Ryan B.} and Chowdhry, {Shakeel A.} and Judy Tsai and Houng, {Aiilyan K.} and Reed, {Guy L.}",
year = "2000",
month = "12",
day = "1",
doi = "10.1074/jbc.M003963200",
language = "English (US)",
volume = "275",
pages = "37686--37691",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "48",

}

TY - JOUR

T1 - Leucine 42 in the fibronectin motif of streptokinase plays a critical role in fibrin-independent plasminogen activation

AU - Liu, Lin

AU - Sazonova, Irina Yurievna

AU - Turner, Ryan B.

AU - Chowdhry, Shakeel A.

AU - Tsai, Judy

AU - Houng, Aiilyan K.

AU - Reed, Guy L.

PY - 2000/12/1

Y1 - 2000/12/1

N2 - The NH2 terminus (residues 1-59) of streptokinase (SK) is a molecular switch that permits fibrin-independent plasminogen activation. Targeted mutations were made in recombinant (r) SK1-59 to identify structural interactions required for this process. Mutagenesis established the functional roles of Phe-37and Glu-39, which were projected to interact with microplasmin in the activator complex. Mutation of Leu-42 (rSK1-59(L42A)), a conserved residue in the SK fibronectin motif that lacks interactions with microplasmin, strongly reduced plasminogen activation (k(cat) decreased 50-fold) but not arnidolysis (k(cat) decreased 1.5-fold). Otherwise rSK1-59(L42A) and native rSK1-59 were indistinguishable in several parameters. Both displayed saturable and specific binding to Glu-plasminogen or the remaining SK fragment (rSKA59). Similarly rSK1-59 and rSK1-59(L42A) bound simultaneously to two different plasminogen molecules, indicating that both plasminogen binding sites were intact. However, when bound to SKΔ59, rSK1-59(L42A) was less effective than rSK1-59 in restructuring the native conformation of the SK A domain, as detected by conformation-dependent monoclonal antibodies. In the light of previous studies, these data provide evidence that SK1-59 contributes to fibrin-independent plasminogen activation through 1) intermolecular inter-actions with the plasmin in the activator complex, 2) binding interactions with the plasminogen substrate, and 3) intramolecular interactions that structure the A domain of SK for Pg substrate processing.

AB - The NH2 terminus (residues 1-59) of streptokinase (SK) is a molecular switch that permits fibrin-independent plasminogen activation. Targeted mutations were made in recombinant (r) SK1-59 to identify structural interactions required for this process. Mutagenesis established the functional roles of Phe-37and Glu-39, which were projected to interact with microplasmin in the activator complex. Mutation of Leu-42 (rSK1-59(L42A)), a conserved residue in the SK fibronectin motif that lacks interactions with microplasmin, strongly reduced plasminogen activation (k(cat) decreased 50-fold) but not arnidolysis (k(cat) decreased 1.5-fold). Otherwise rSK1-59(L42A) and native rSK1-59 were indistinguishable in several parameters. Both displayed saturable and specific binding to Glu-plasminogen or the remaining SK fragment (rSKA59). Similarly rSK1-59 and rSK1-59(L42A) bound simultaneously to two different plasminogen molecules, indicating that both plasminogen binding sites were intact. However, when bound to SKΔ59, rSK1-59(L42A) was less effective than rSK1-59 in restructuring the native conformation of the SK A domain, as detected by conformation-dependent monoclonal antibodies. In the light of previous studies, these data provide evidence that SK1-59 contributes to fibrin-independent plasminogen activation through 1) intermolecular inter-actions with the plasmin in the activator complex, 2) binding interactions with the plasminogen substrate, and 3) intramolecular interactions that structure the A domain of SK for Pg substrate processing.

UR - http://www.scopus.com/inward/record.url?scp=0034529160&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034529160&partnerID=8YFLogxK

U2 - 10.1074/jbc.M003963200

DO - 10.1074/jbc.M003963200

M3 - Article

C2 - 10961989

AN - SCOPUS:0034529160

VL - 275

SP - 37686

EP - 37691

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 48

ER -