Structural characterization and cytolytic activity of a potent antimicrobial motif in longicin, a defensin-like peptide in the tick Haemaphysalis longicornis.

Autor: Rahman M; Department of Frontier Veterinary Medicine, Kagoshima University, Korimoto, Kagoshima 890-0065, Japan., Tsuji N, Boldbaatar D, Battur B, Liao M, Umemiya-Shirafuji R, You M, Tanaka T, Fujisaki K
Jazyk: angličtina
Zdroj: The Journal of veterinary medical science [J Vet Med Sci] 2010 Feb; Vol. 72 (2), pp. 149-56. Date of Electronic Publication: 2009 Nov 25.
DOI: 10.1292/jvms.09-0167
Abstrakt: Longicin, a defensin-like peptide, was recently identified in the hard tick Haemaphysalis longicornis. Longicin and one of its synthetic partial analogs (P4) displayed antimicrobial/fungicidal/parasiticidal activity. In the present study, we compared longicin-derived synthetic analogs in order to characterize the antimicrobial motif (P4) by analyzing some structural features using various bioinformatic tools and/or CD spectroscopy. According to the chemicophysical characteristics, P4 is suggested to be a cationic peptide with hydrophobic and amphipathic character. The predicted secondary structure indicated the existence of a beta-sheet, which was also observed in the modeled tertiary structure. CD spectroscopic results also showed the existence of a beta-sheet and transition to a helical conformation in the presence of membrane-mimicking conditions. These structural observations on P4 suggested that the antimicrobial activity could be due to the beta-sheet as well as the alpha-helix. In addition, a sequence homology search showed that molecules identified in other ticks and organisms also have the P4 analogous domain at their C-terminal, which indicates P4 as a conserved domain. The peptide P4 also showed low cytolytic activity. Based on the present result and previously reported studies, the peptide P4 could be suggested as a novel antimicrobial domain indicating future therapeutic agent against bacteria.
Databáze: MEDLINE