Domain 5 of High Molecular Weight Kininogen Is Antibacterial

Emma Andersson Nordahl, Victoria Rydengård, Matthias Mörgelin, Artur Schmidtchen
2005 Journal of Biological Chemistry  
Antimicrobial peptides are important effectors of the innate immune system. These peptides belong to a multifunctional group of molecules that apart from their antibacterial activities also interact with mammalian cells and glycosaminoglycans and control chemotaxis, apoptosis, and angiogenesis. Here we demonstrate a novel antimicrobial activity of the heparin-binding and cell-binding domain 5 of high molecular weight kininogen. Antimicrobial epitopes of domain 5 were characterized by analysis
more » ... overlapping peptides. A peptide, HKH20 (His 479 -His 498 ), efficiently killed the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa and the Gram-positive Enterococcus faecalis. Fluorescence microscopy and electron microscopy demonstrated that HKH20 binds to and induces breaks in bacterial membranes. Furthermore, no discernible hemolysis or membrane-permeabilizing effects on eukaryotic cells were noted. Proteolytic degradation of high molecular weight kininogen by neutrophil-derived proteases as well as the metalloproteinase elastase from P. aeruginosa yielded fragments comprising HKH20 epitopes, indicating that kininogen-derived antibacterial peptides are released during proteolysis. . 2 The abbreviations used are: AMP, antimicrobial peptide; HMWK, high molecular weight kininogen; D5, domain 5; rD5, recombinant domain 5; RDA, radial diffusion assays; PBS, phosphate-buffered saline; LDH, lactate dehydrogenase; MEC, minimal effective concentration; cfu, colony-forming units; DMEM, Dulbecco's modified Eagle's medium; MALDI-TOF, matrix-assisted laser desorption ionization time-of-flight; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; Tricine, N-[2-hydroxy-1, 1-bis(hydroxymethyl)ethyl]glycine.
doi:10.1074/jbc.m507249200 pmid:16091369 fatcat:6ezx3c33ajbb7myuxfkxlo46vy