Convertase inhibitory properties of Staphylococcal extracellular complement-binding protein

J Biol Chem. 2010 May 14;285(20):14973-14979. doi: 10.1074/jbc.M109.091975. Epub 2010 Mar 19.


The human pathogen Staphylococcus aureus secretes several complement evasion molecules to combat the human immune response. Extracellular complement-binding protein (Ecb) binds to the C3d domain of C3 and thereby blocks C3 convertases of the alternative pathway and C5 convertases via all complement pathways. Inhibition of C5 convertases results in complete inhibition of C5a generation and subsequent neutrophil migration. Here, we show that binding of Ecb to the C3d domain of C3b is crucial for inhibition of C5 convertases. Ecb does not interfere with substrate binding to convertases but prevents formation of an active convertase enzyme.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Complement C3-C5 Convertases / antagonists & inhibitors
  • Complement C3-C5 Convertases / metabolism*
  • Enzyme-Linked Immunosorbent Assay
  • Protein Binding
  • Staphylococcus aureus / enzymology*


  • Complement C3-C5 Convertases