Pardaxin permeabilizes vesicles more efficiently by pore formation than by disruption

TY - JOUR

T1 - Pardaxin permeabilizes vesicles more efficiently by pore formation than by disruption

AU - Vad, Brian S

AU - Bertelsen, Kresten

AU - Johansen, Charlotte Hau

AU - Pedersen, Jan Mondrup

AU - Skrydstrup, Troels

AU - Nielsen, Niels Christian

AU - Otzen, Daniel E

N1 - Copyright 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

PY - 2010/2/17

Y1 - 2010/2/17

N2 - Pardaxin is a 33-amino-acid neurotoxin from the Red Sea Moses sole Pardachirus marmoratus, whose mode of action shows remarkable sensitivity to lipid chain length and charge, although the effect of pH is unclear. Here we combine optical spectroscopy and dye release experiments with laser scanning confocal microscopy and natural abundance (13)C solid-state nuclear magnetic resonance to provide a more complete picture of how pardaxin interacts with lipids. The kinetics and efficiency of release of entrapped calcein is highly sensitive to pH. In vesicles containing zwitterionic lipids (PC), release occurs most rapidly at low pH, whereas in vesicles containing 20% anionic lipid (PG), release occurs most rapidly at high pH. Pardaxin forms stable or transient pores in PC vesicles that allow release of contents without loss of vesicle integrity, whereas the inclusion of PG promotes total vesicle collapse. In agreement with this, solid-state nuclear magnetic resonance reveals that pardaxin takes up a trans-membrane orientation in 14-O-PC/6-O-PC bicelles, whereas the inclusion of 14-0-PG restricts it to contacts with lipid headgroups, promoting membrane lysis. Pore formation in zwitterionic vesicles is more efficient than lysis of anionic vesicles, suggesting that electrostatic interactions may trap pardaxin in several suboptimal interconverting conformations on the membrane surface.

AB - Pardaxin is a 33-amino-acid neurotoxin from the Red Sea Moses sole Pardachirus marmoratus, whose mode of action shows remarkable sensitivity to lipid chain length and charge, although the effect of pH is unclear. Here we combine optical spectroscopy and dye release experiments with laser scanning confocal microscopy and natural abundance (13)C solid-state nuclear magnetic resonance to provide a more complete picture of how pardaxin interacts with lipids. The kinetics and efficiency of release of entrapped calcein is highly sensitive to pH. In vesicles containing zwitterionic lipids (PC), release occurs most rapidly at low pH, whereas in vesicles containing 20% anionic lipid (PG), release occurs most rapidly at high pH. Pardaxin forms stable or transient pores in PC vesicles that allow release of contents without loss of vesicle integrity, whereas the inclusion of PG promotes total vesicle collapse. In agreement with this, solid-state nuclear magnetic resonance reveals that pardaxin takes up a trans-membrane orientation in 14-O-PC/6-O-PC bicelles, whereas the inclusion of 14-0-PG restricts it to contacts with lipid headgroups, promoting membrane lysis. Pore formation in zwitterionic vesicles is more efficient than lysis of anionic vesicles, suggesting that electrostatic interactions may trap pardaxin in several suboptimal interconverting conformations on the membrane surface.

KW - Amino Acid Sequence

KW - Fish Venoms

KW - Fluoresceins

KW - Hydrogen-Ion Concentration

KW - Kinetics

KW - Lipid Metabolism

KW - Lipids

KW - Magnetic Resonance Spectroscopy

KW - Microscopy, Confocal

KW - Molecular Sequence Data

KW - Permeability

KW - Porosity

KW - Protein Conformation

KW - Protons

KW - Unilamellar Liposomes

U2 - 10.1016/j.bpj.2009.08.063

DO - 10.1016/j.bpj.2009.08.063

M3 - Journal article

C2 - 20159154

SN - 0006-3495

VL - 98

SP - 576

EP - 585

JO - Biophysical Journal

JF - Biophysical Journal

IS - 4

ER -