ISOLATION, ANTIMICROBIAL ACTIVITIES, AND PRIMARY STRUCTURES OF HAMSTER NEUTROPHIL DEFENSINS

Hamster (Mesocricetus auratus) neutrophil granules contain at least fo ur microbicidal peptides belonging to the defensin family. These compo unds were purified from granule acid extracts by reverse-phase chromat ography and termed HaNP-1 to -4 (hamster neutrophil peptide). HaNP-1 a nd HaNP-3 revealed the most bactericidal activity, with a 50% inhibito ry concentration of 0.3 to 0.8 mu g/ml for Staphylococcus aureus and S treptococcus pyogenes strains. The HaNP-4 was always isolated in conce ntrations exceeding about 10 times the concentrations of other hamster peptides, but its antibacterial activity as well that of HaNP-2 was r elatively lower, probably as a result of conserved Arg residue substit utions. Other microorganisms were also tested, and generally, hamster defensins exhibited less potency against gram-negative bacteria. The a mino acid sequence of hamster defensins showed a high percentage of id entity to the sequence of mouse enteric defensins, reaching about 60% identical residues in the case of HaNP-3 and cryptdin 3.