Identification of an anti-mycobacterial domain in NK-lysin and granulysin.
NK-lysin and granulysin are homologous cationic anti-bacterial peptides produced by pig and human cytolytic lymphocytes, respectively. The solution structure of NK-lysin comprises five amphipathic alpha-helices. To investigate the properties of a helix-loop-helix region postulated to be a membrane-docking part of NK-lysin, we synthesized 22- and 29-residue peptides reproducing this region for both NK-lysin and granulysin. CD spectroscopy of the synthetic peptides in a liposomal solution showed spectra typical of alpha-helical peptides. The peptides were active against Gram-positive and Gram-negative bacteria, with the two NK-lysin peptides showing higher anti-bacterial activities than the two from granulysin. One NK-lysin peptide was active against Pseudomonas aeruginosa and Staphylococcus aureus, two organisms against which NK-lysin is inactive. Granulysin peptides were inactive against these bacteria, in contrast with granulysin, which is known to be active against them. Both NK-lysin and all synthetic analogues killed Mycobacterium tuberculosis and K562 tumour cells, but did not display haemolytic activity. These results identify a potent anti-mycobacterial domain in NK-lysin and granulysin consisting of a 22-residue (helix 3) sequence plus a disulphide-constrained loop.
Andreu
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D
Department of Organic Chemistry, University of Barcelona, E-08028 Barcelona, Spain.
Carreño
C
C
Linde
C
C
Boman
H G
HG
Andersson
M
M
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000737:chemistry* / Q000494:pharmacology; D001410:Bacillus megaterium / Q000187:drug effects; D002942:Circular Dichroism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis; D017433:Protein Structure, Secondary; D011510:Proteolipids / Q000737:chemistry* / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D011663:Pulmonary Surfactants / Q000737:chemistry* / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000187:drug effects; D013552:Swine
D000900:Anti-Bacterial Agents; D000945:Antigens, Differentiation, T-Lymphocyte; C075005:GNLY protein, human; C093238:NK-lysin; D010446:Peptide Fragments; D011510:Proteolipids; D011663:Pulmonary Surfactants