Electrostatic interactions, but not the YGNGV consensus motif, govern the binding of pediocin PA-1 and its fragments to phospholipid vesicles.
AUTOR(ES)
Chen, Y
RESUMO
The purpose of this study was to characterize in detail the binding of pediocin PA-1 and its fragments to target membranes by using tryptophan fluorescence as a probe. Based on a three-dimensional model (Y. Chen, R. Shapira, M. Eisenstein, and T. J. Montville, Appl. Environ. Microbiol. 63:524-531, 1997), four synthetic N-terminal pediocin fragments were selected to study the mechanism of the initial step by which the bacteriocin associates with membranes. Binding of pediocin PA-1 to vesicles of phosphatidylglycerol, the major component of Listeria membranes, caused an increase in the intrinsic tryptophan fluorescence intensity with a blue shift of the emission maximum. The Stern-Volmer constants for acrylamide quenching of the fluorescence of pediocin PA-1 in buffer and in the lipid vesicles were 8.83 +/- 0.42 and 3.53 +/- 0.67 M-1, respectively, suggesting that the tryptophan residues inserted into the hydrophobic core of the lipid bilayer. The synthetic pediocin fragments bound strongly to the lipid vesicles when a patch of positively charged amino acid residues (K-11 and H-12) was present but bound weakly when this patch was mutated out. Quantitative comparison of changes in tryptophan fluorescence parameters, as well as the dissociation constants for pediocin PA-1 and its fragments, revealed that the relative affinity to the lipid vesicles paralleled the net positive charge in the peptide. The relative affinity for the fragment containing the YGNGV consensus motif was 10-fold lower than that for the fragment containing the positive patch. Furthermore, changing the pH from 6.0 to 8.0 decreased binding of the fragments containing the positive patch, probably due to deprotonation of His residues. These results demonstrate that electrostatic interactions, but not the YGNGV motif, govern pediocin binding to the target membrane.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=168800Documentos Relacionados
- Influence of Lipid Composition on Pediocin PA-1 Binding to Phospholipid Vesicles†
- Enhanced Production of Pediocin PA-1 and Coproduction of Nisin and Pediocin PA-1 by Lactococcus lactis
- Electrostatic binding of proteins to membranes. Theoretical predictions and experimental results with charybdotoxin and phospholipid vesicles.
- Binding of Pediocin PA-1 with Anionic Lipid Induces Model Membrane Destabilization
- Functional characterization of pediocin PA-1 binding to liposomes in the absence of a protein receptor and its relationship to a predicted tertiary structure.