Group A streptococcal isolate 64/14 expresses surface plasmin-binding structures in addition to Plr

Res Microbiol. Sep-Oct 1997;148(7):559-72. doi: 10.1016/S0923-2508(97)88080-1.


A recombinant plasmin receptor (Plr) gene product originally cloned from group A streptococcal isolate 64/14 was analysed for its ability to bind plasmin(ogen) and to account for all the surface plasmin-binding properties of streptococcal isolate 64/14. Functional analysis of recombinant Plr demonstrated that the protein exhibited equal reactivity with human Lys-plasmin and Lys-plasminogen, but significantly lower reactivity with Glu-plasminogen. Plasmin-binding was both inhibitable and elutable by lysine or lysine analogs, and active plasmin bound to recombinant Plr was not neutralized by alpha 2-antiplasmin. Thus, the plasmin-binding properties of recombinant Plr correlated with the plasmin-binding phenotype of the intact streptococcal isolate 64/14. In addition, fluid-phase recombinant Plr could completely inhibit binding of plasmin to either immobilized recombinant Plr or group A streptococcal isolate 64/14 with equal efficiency, indicating that surface-expressed Plr could account for all the plasmin-binding properties of the intact organism. An IgM monoclonal antibody to recombinant Plr that specifically recognized a surface structure on streptococcal isolate 64/14 significantly inhibited the binding of plasmin to the recombinant protein; however, the antibody was not successful at inhibiting plasmin-binding to the intact bacteria, indicating the presence of other plasmin-binding structures on the bacterial surface in addition to Plr.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antibodies, Monoclonal / metabolism
  • Antibody Specificity
  • Bacterial Outer Membrane Proteins / immunology
  • Bacterial Outer Membrane Proteins / metabolism*
  • Bacterial Proteins*
  • Fibrinolysin / metabolism
  • Humans
  • Immunoglobulin M / metabolism
  • Mice
  • Mice, Inbred BALB C
  • Microscopy, Immunoelectron
  • Phenotype
  • Plasminogen / immunology
  • Plasminogen / metabolism
  • Receptors, Peptide / metabolism*
  • Recombinant Proteins / immunology
  • Recombinant Proteins / metabolism
  • Streptococcus pyogenes / chemistry*
  • Streptococcus pyogenes / genetics
  • Streptococcus pyogenes / metabolism


  • Antibodies, Monoclonal
  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • Immunoglobulin M
  • Plr protein, Streptococcus
  • Receptors, Peptide
  • Recombinant Proteins
  • Plasminogen
  • Fibrinolysin