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Effects on human plasminogen conformation and activation rate caused by interaction with VEK-30, a peptide derived

Mariana Figuera-Losada1, Marie Ranson, Martina L Sanderson-Smith

  • 1W.M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, IN 46556, USA.

Biochimica Et Biophysica Acta
|February 16, 2010
PubMed

Insights

Group A Streptococcus virulence involves bacterial protein PAM binding to human plasminogen (Pg). This interaction, mediated by PAM

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Microbiology

Background:

  • Fibrinolysis in vertebrates is primarily mediated by plasmin (Pm), derived from plasminogen (Pg).
  • Plasminogen features five kringle domains with conserved Lys-binding sites (LBS) crucial for molecular interactions.
  • The K2 domain's LBS atypicaly interacts with the bacterial protein PAM, linked to Group A Streptococcus invasiveness.

Purpose of the Study:

  • To investigate the impact of the PAM-plasminogen interaction on plasminogen zymogen activation and conformation.
  • To determine if the VEK-30 peptide, derived from PAM, affects plasminogen activation.
  • To elucidate the mechanism underlying Group A Streptococcal virulence related to plasminogen binding.

Main Methods:

  • Sedimentation velocity analysis to assess plasminogen conformation changes.
  • Enzyme kinetics to measure plasminogen activation rates in the presence of VEK-30 and PAM.
  • Comparative analysis with small-molecule plasminogen activators.

Main Results:

  • VEK-30 binding minimally affected plasminogen's sedimentation velocity coefficients.
  • A direct correlation was observed between VEK-30 or PAM concentration and plasminogen activation rate.
  • These effects contrast with significant conformational changes induced by small-molecule activators.

Conclusions:

  • The interaction between PAM and plasminogen does not induce major conformational changes in plasminogen.
  • Bacterial protein PAM directly influences plasminogen activation rate, suggesting a novel activation mechanism.
  • This PAM-mediated plasminogen activation may represent a key factor in Group A Streptococcal virulence.

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