Roles of salt and conformation in the biological and physicochemical behavior of protegrin-1 and designed analogues

Correlation of antimicrobial, hemolytic, and lipid bilayer-perturbing activities

Jonathan R. Lai, Raquel F. Epand, Bernard Weisblum, Richard M. Epand, Samuel H. Gellman

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Protegrins are short (16-18 residues) cationic peptides from porcine leukocytes that display potent, broad-spectrum antimicrobial activity. Protegrin-1 (PG-1), one of five natural homologues, adopts a rigid β-hairpin structure that is stabilized by two disulfide bonds. We have previously employed the principles of β-hairpin design to develop PG-1 variants that lack disulfide bonds but nevertheless display potent antimicrobial activity [Lai, J. R., Huck, B. R., Weisblum, B., and Gellman, S. H. (2002) Biochemistry 41, 12835-12842.]. The activity of these disulfide-free variants, however, is attenuated in the presence of salt, and the activity of PG-1 itself is not. Salt-induced inactivation of host-defense peptides, such as human defensins, is thought to be important in some pathological situations (e.g., cystic fibrosis), and the variation in salt-sensitivity among our PG-1 analogues offers a model system with which to explore the origins of these salt effects. We find that the variations in antimicrobial activity among our peptides are correlated with the folding propensities of these molecules and with the extent to which the peptides induce leakage of contents from synthetic liposomes. Comparable correlations were observed between folding and hemolytic activity. The extent to which added salt reduces antimicrobial activity parallels salt effects on vesicle perturbation, which suggests that the biological effects of high salt concentrations arise from modulation of peptide-membrane interactions.

Original languageEnglish (US)
Pages (from-to)15718-15730
Number of pages13
JournalBiochemistry
Volume45
Issue number51
DOIs
StatePublished - Dec 26 2006
Externally publishedYes

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Lipid bilayers
Lipid Bilayers
Conformations
Salts
Peptides
Disulfides
Rigid structures
Defensins
Biochemistry
protegrin-1
Cystic Fibrosis
Liposomes
Leukocytes
Swine
Modulation
Membranes
Molecules

ASJC Scopus subject areas

  • Biochemistry

Cite this

Roles of salt and conformation in the biological and physicochemical behavior of protegrin-1 and designed analogues : Correlation of antimicrobial, hemolytic, and lipid bilayer-perturbing activities. / Lai, Jonathan R.; Epand, Raquel F.; Weisblum, Bernard; Epand, Richard M.; Gellman, Samuel H.

In: Biochemistry, Vol. 45, No. 51, 26.12.2006, p. 15718-15730.

Research output: Contribution to journalArticle

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