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Title: Melittin binding to mixed phosphatidylglycerol/phosphatidylcholine membranes

Abstract

The binding of bee venom melittin to negatively charged unilamellar vesicles and planar lipid bilayers composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) was studied with circular dichroism and deuterium NMR spectroscopy. The melittin binding isotherm was measured for small unilamellar vesicles containing 10 or 20 mol % POPG. Due to electrostatic attraction, binding of the positively charged melittin was much enhanced as compared to the binding to neutral lipid vesicles. However, after correction for electrostatic effects by means of the Gouy-Chapman theory, all melittin binding isotherms could be described by a partition Kp = (4.5 +/- 0.6) x 10(4) M-1. It was estimated that about 50% of the total melittin surface was embedded in a hydrophobic environment. The melittin partition constant for small unilamellar vesicles was by a factor of 20 larger than that of planar bilayers and attests to the tighter lipid packing in the nonsonicated bilayers. Deuterium NMR studies were performed with coarse lipid dispersions. Binding of melittin to POPC/POPG (80/20 mol/mol) membranes caused systematic changes in the conformation of the phosphocholine and phosphoglycerol head groups which were ascribed to the influence of electrostatic charge on the choline dipole. While the negative charge of phosphatidylglycerol moved the N+more » end of the choline -P-N+ dipole toward the bilayer interior, the binding of melittin reversed this effect and rotated the N+ end toward the aqueous phase. No specific melittin-POPG complexes could be detected. The phosphoglycerol head group was less affected by melittin binding than its choline counterpart.« less

Authors:
;  [1]
  1. Univ. of Basel (Switzerland)
Publication Date:
OSTI Identifier:
6949002
Resource Type:
Journal Article
Journal Name:
Biochemistry; (USA)
Additional Journal Information:
Journal Volume: 29:1; Journal ID: ISSN 0006-2960
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; PHOSPHOLIPIDS; MOLECULAR STRUCTURE; VENOMS; BIOCHEMICAL REACTION KINETICS; BEES; BIOELECTRICITY; CHOLINE; DEUTERIUM; NUCLEAR MAGNETIC RESONANCE; PROTEIN STRUCTURE; TRACER TECHNIQUES; ALCOHOLS; AMINES; AMMONIUM COMPOUNDS; ANIMALS; ARTHROPODS; DRUGS; ELECTRICITY; ESTERS; HYDROGEN ISOTOPES; HYDROXY COMPOUNDS; HYMENOPTERA; INSECTS; INVERTEBRATES; ISOTOPE APPLICATIONS; ISOTOPES; KINETICS; LIGHT NUCLEI; LIPIDS; LIPOTROPIC FACTORS; MAGNETIC RESONANCE; NUCLEI; ODD-ODD NUCLEI; ORGANIC COMPOUNDS; ORGANIC PHOSPHORUS COMPOUNDS; QUATERNARY COMPOUNDS; REACTION KINETICS; RESONANCE; STABLE ISOTOPES; 550201* - Biochemistry- Tracer Techniques

Citation Formats

Beschiaschvili, G, and Seelig, J. Melittin binding to mixed phosphatidylglycerol/phosphatidylcholine membranes. United States: N. p., 1990. Web. doi:10.1021/bi00453a007.
Beschiaschvili, G, & Seelig, J. Melittin binding to mixed phosphatidylglycerol/phosphatidylcholine membranes. United States. https://doi.org/10.1021/bi00453a007
Beschiaschvili, G, and Seelig, J. Tue . "Melittin binding to mixed phosphatidylglycerol/phosphatidylcholine membranes". United States. https://doi.org/10.1021/bi00453a007.
@article{osti_6949002,
title = {Melittin binding to mixed phosphatidylglycerol/phosphatidylcholine membranes},
author = {Beschiaschvili, G and Seelig, J},
abstractNote = {The binding of bee venom melittin to negatively charged unilamellar vesicles and planar lipid bilayers composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) was studied with circular dichroism and deuterium NMR spectroscopy. The melittin binding isotherm was measured for small unilamellar vesicles containing 10 or 20 mol % POPG. Due to electrostatic attraction, binding of the positively charged melittin was much enhanced as compared to the binding to neutral lipid vesicles. However, after correction for electrostatic effects by means of the Gouy-Chapman theory, all melittin binding isotherms could be described by a partition Kp = (4.5 +/- 0.6) x 10(4) M-1. It was estimated that about 50% of the total melittin surface was embedded in a hydrophobic environment. The melittin partition constant for small unilamellar vesicles was by a factor of 20 larger than that of planar bilayers and attests to the tighter lipid packing in the nonsonicated bilayers. Deuterium NMR studies were performed with coarse lipid dispersions. Binding of melittin to POPC/POPG (80/20 mol/mol) membranes caused systematic changes in the conformation of the phosphocholine and phosphoglycerol head groups which were ascribed to the influence of electrostatic charge on the choline dipole. While the negative charge of phosphatidylglycerol moved the N+ end of the choline -P-N+ dipole toward the bilayer interior, the binding of melittin reversed this effect and rotated the N+ end toward the aqueous phase. No specific melittin-POPG complexes could be detected. The phosphoglycerol head group was less affected by melittin binding than its choline counterpart.},
doi = {10.1021/bi00453a007},
url = {https://www.osti.gov/biblio/6949002}, journal = {Biochemistry; (USA)},
issn = {0006-2960},
number = ,
volume = 29:1,
place = {United States},
year = {1990},
month = {1}
}