Functional characterization of pediocin PA-1 binding to liposomes in the absence of a protein receptor and its relationshipto a predicted tertiary structure

Yuhuan Chen, Roni Shapira, Miriam Eisenstein, Thomas J. Montville*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

91 Scopus citations

Abstract

The physicochemical interaction of pediocin PA-1 with target membranes was characterized using lipid vesicles made from the total lipids extracted from Listeria monocytogenes. Pediocin PA-1 caused the time- and concentration-dependent release of entrapped carboxyfluorescein (CF) from the vesicles. The pediocin-induced CF efflux rates were higher under acidic conditions than under neutral and alkaline conditions and were dependent on both pediocin and lipid concentrations. A binding isotherm constructed on the basis of the Langmuir isotherm gave an apparent binding constant of 1.4 x 107 M-1 at pH 6.0. The imposition of a transmembrane potential (inside negative) increased the CF efflux rate by 88%. Pediocin PA-1 also permeablized synthetic vesicles composed only of phosphatidylcholine. Sequence alignments and secondary-structure predictions for the N terminus of pediocin PA-1 and other class IIa bacteriocins predicted that pediocin PA-1 contained two β-sheets maintained in a hairpin conformation stabilized by a disulfide bridge. The structural model also revealed patches of positively charged residues, consistent with the argument that electrostatic interactions play an important role in the binding of pediocin PA-1 to the lipid vesicles. This study demonstrates that pediocin PA-1 can function in the absence of a protein receptor and provides a structural model consistent with these results.

Original languageAmerican English
Pages (from-to)524-531
Number of pages8
JournalApplied and Environmental Microbiology
Volume63
Issue number2
DOIs
StatePublished - Feb 1997

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