2jos: Difference between revisions

Revision as of 19:04, 21 February 2008

Solution structure of piscidin in presence of DPC micelles

OverviewOverview

Piscidin, an antibacterial peptide isolated from the mast cells of striped bass, has potent antimicrobial activity against a broad spectrum of pathogens in vitro. We investigated the mechanism of action of this 22-residue cationic peptide by carrying out structural studies and electrophysiological experiments in lipid bilayers. Circular dichroism experiments showed that piscidin was unstructured in water but had a high alpha-helix content in dodecylphosphocholine (DPC) micelles. 1H NMR data in water and TFE confirmed these results and demonstrated that the segment of residues 8-17 adopted an alpha-helical structure in a micellar environment. This molecule has a marked amphipathic character, due to well-defined hydrophobic and hydrophilic sectors. This structure is similar to those determined for other cationic peptides involved in permeabilization of the bacterial membrane. Multichannel experiments with piscidin incorporated into azolectin planar bilayers gave reproducible I-V curves at various peptide concentrations and unambiguously showed that this peptide permeabilized the membrane. This pore forming activity was confirmed by single-channel experiments, with well-defined ion channels obtained at different voltages. The characteristics of the ion channels (voltage dependence, only one or two states of conductance) clearly suggest that piscidin is more likely to permeabilize the membrane by toroidal pore formation rather than via the "barrel-stave" mechanism.

About this StructureAbout this Structure

2JOS is a Single protein structure of sequence from [1]. Full crystallographic information is available from OCA.

ReferenceReference

Structure and mechanism of action of the antimicrobial peptide piscidin., Campagna S, Saint N, Molle G, Aumelas A, Biochemistry. 2007 Feb 20;46(7):1771-8. Epub 2007 Jan 25. PMID:17253775

Page seeded by OCA on Thu Feb 21 18:04:42 2008

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 ==Overview==
-Piscidin, an antibacterial peptide isolated from the mast cells of striped, bass, has potent antimicrobial activity against a broad spectrum of, pathogens in vitro. We investigated the mechanism of action of this, 22-residue cationic peptide by carrying out structural studies and, electrophysiological experiments in lipid bilayers. Circular dichroism, experiments showed that piscidin was unstructured in water but had a high, alpha-helix content in dodecylphosphocholine (DPC) micelles. 1H NMR data, in water and TFE confirmed these results and demonstrated that the segment, of residues 8-17 adopted an alpha-helical structure in a micellar, environment. This molecule has a marked amphipathic character, due to, well-defined hydrophobic and hydrophilic sectors. This structure is, similar to those determined for other cationic peptides involved in, permeabilization of the bacterial membrane. Multichannel experiments with, piscidin incorporated into azolectin planar bilayers gave reproducible I-V, curves at various peptide concentrations and unambiguously showed that, this peptide permeabilized the membrane. This pore forming activity was, confirmed by single-channel experiments, with well-defined ion channels, obtained at different voltages. The characteristics of the ion channels, (voltage dependence, only one or two states of conductance) clearly, suggest that piscidin is more likely to permeabilize the membrane by, toroidal pore formation rather than via the "barrel-stave" mechanism.
+Piscidin, an antibacterial peptide isolated from the mast cells of striped bass, has potent antimicrobial activity against a broad spectrum of pathogens in vitro. We investigated the mechanism of action of this 22-residue cationic peptide by carrying out structural studies and electrophysiological experiments in lipid bilayers. Circular dichroism experiments showed that piscidin was unstructured in water but had a high alpha-helix content in dodecylphosphocholine (DPC) micelles. 1H NMR data in water and TFE confirmed these results and demonstrated that the segment of residues 8-17 adopted an alpha-helical structure in a micellar environment. This molecule has a marked amphipathic character, due to well-defined hydrophobic and hydrophilic sectors. This structure is similar to those determined for other cationic peptides involved in permeabilization of the bacterial membrane. Multichannel experiments with piscidin incorporated into azolectin planar bilayers gave reproducible I-V curves at various peptide concentrations and unambiguously showed that this peptide permeabilized the membrane. This pore forming activity was confirmed by single-channel experiments, with well-defined ion channels obtained at different voltages. The characteristics of the ion channels (voltage dependence, only one or two states of conductance) clearly suggest that piscidin is more likely to permeabilize the membrane by toroidal pore formation rather than via the "barrel-stave" mechanism.
 ==About this Structure==
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 [[Category: piscidin]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jan 29 20:54:19 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:04:42 2008''