Proteinases of common pathogenic bacteria degrade and inactivate the antibacterial peptide LL-37

Artur Schmidtchen, Inga-Maria Frick, Emma Andersson, Hans Tapper, Lars Björck

Research output: Contribution to journalArticlepeer-review

324 Citations (SciVal)
269 Downloads (Pure)


Effectors of the innate immune system, the anti-bacterial peptides, have pivotal roles in preventing infection at epithelial surfaces. Here we show that proteinases of the significant human pathogens Pseudomonas aeruginosa, Enterococcus faecalis, Proteus mirabilis and Streptococcus pyogenes, degrade the antibacterial peptide LL-37. Analysis by mass spectrometry of fragments generated by P. aeruginosa elastase in vitro revealed that the initial cleavages occurred at Asn-Leu and Asp-Phe, followed by two breaks at Arg-Ile, thus inactivating the peptide. Proteinases of the other pathogens also degraded LL-37 as determined by SDS-PAGE. Ex vivo, P. aeruginosa elastase induced LL-37 degradation in human wound fluid, leading to enhanced bacterial survival. The degradation was blocked by the metalloproteinase inhibitors GM6001 and 1, 10-phenantroline (both of which inhibited P. aeruginosa elastase, P. mirabilis proteinase, and E. faecalis gelatinase), or the inhibitor E64 (which inhibited S. pyogenes cysteine proteinase). Additional experiments demonstrated that dermatan sulphate and disaccharides of the structure [DeltaUA(2S)-GalNAc(4,6S)], or sucroseoctasulphate, in-hibited the degradation of LL-37. The results indicate that proteolytic degradation of LL-37 is a common virulence mechanism and that molecules which block this degradation could have therapeutic potential.
Original languageEnglish
Pages (from-to)157-168
JournalMolecular Microbiology
Issue number1
Publication statusPublished - 2002

Subject classification (UKÄ)

  • Dermatology and Venereal Diseases


  • Endopeptidases/*metabolism
  • Glycosaminoglycans/pharmacology
  • Microbial Sensitivity Tests
  • Human
  • Molecular Sequence Data
  • Pancreatic Elastase/metabolism
  • Neutrophils
  • Protease Inhibitors/pharmacology
  • Pseudomonas aeruginosa/enzymology/pathogenicity
  • Spectrum Analysis
  • Mass
  • Sulfur/metabolism
  • Wound Infection/microbiology
  • Virulence
  • Disaccharides/chemistry/pharmacology
  • Bacterial Infections/microbiology
  • Bacteria/*drug effects/*metabolism/pathogenicity
  • Antimicrobial Cationic Peptides/genetics/*metabolism/*pharmacology
  • Amino Acid Sequence


Dive into the research topics of 'Proteinases of common pathogenic bacteria degrade and inactivate the antibacterial peptide LL-37'. Together they form a unique fingerprint.

Cite this