Plasminogen interaction and activation on Streptococcus mutans surface.

Area of Science:

• Microbiology
• Biochemistry
• Molecular Biology

Background:

• Pathogenic microorganisms can bind plasminogen, and its activation to plasmin contributes to virulence.
• Streptococcus mutans is a significant oral pathogen implicated in various infections.

Purpose of the Study:

• To investigate the interaction between Streptococcus mutans and human plasminogen.
• To determine the mechanism of plasminogen binding and its functional consequences for S. mutans virulence.

Main Methods:

• Studying the binding of human plasminogen and plasmin to S. mutans.
• Investigating the role of lysine-binding sites using inhibitors like L-lysine and epsilon-aminocaproic acid.
• Assessing the effect of S. mutans on plasminogen activation by tissue plasminogen activator and urokinase.
• Analyzing proteolytic activity using zymogram analysis.

Main Results:

• Streptococcus mutans effectively binds both human plasminogen and plasmin.
• Plasminogen binding is mediated by lysine-binding sites, as evidenced by inhibition with L-lysine and epsilon-aminocaproic acid.
• S. mutans enhances plasminogen activation by tissue plasminogen activator in a cell-concentration-dependent manner.
• Zymogram analysis revealed that acquired plasmin activity is the predominant proteolytic activity in S. mutans.

Conclusions:

• Streptococcus mutans acquires host plasminogen and plasmin, suggesting a mechanism for enhancing virulence.
• The interaction involves specific lysine-binding sites on plasminogen.
• Acquired proteolytic activity via plasmin may contribute to the infective process of S. mutans.