Effect of bile salts on monolayer curvature of a phosphatidylethanolamine/water model membrane system

R. L. Thurmond, G. Lindblom, Michael F Brown

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

A partial phase diagram of the ternary system dioleoylphosphatidylethanolamine (DOPE)/sodium cholate/water has been determined using 31P Nuclear Magnetic Resonance (NMR) spectroscopy. In the absence of cholate, it is well known that the DOPE/water system forms a reversed hexagonal (H(II)) phase. We have found that addition of even small amounts of cholate to the DOPE/water system leads to a transition to a lamellar (L(α)) phase. At higher cholate concentrations, a cubic (I) phase (low water content) or a micellar solution (L1) phase (high water content) is present. Thus, cholate molecules have a strong tendency to alter the lipid monolayer curvature. Increasing the concentration of cholate changes the curvature of DOPE from negative (H(II) phase), through zero (L(α) phase), and finally to a phase of positive curvature (micellar solution). This observation can be rationalized in terms of the molecular structure of cholate, which is amphipathic and has one hydrophobic and one hydrophilic side of the steroid ring system. The cholate molecules have a tendency to lie flat on the lipid aggregate surface, thereby increasing the effective interfacial area of the polar head groups, and altering the curvature free energy of the system.

Original languageEnglish (US)
Pages (from-to)728-732
Number of pages5
JournalBiophysical Journal
Volume60
Issue number3
StatePublished - 1991

Fingerprint

Cholates
Bile Acids and Salts
Membranes
Water
Sodium Cholate
Lipids
phosphatidylethanolamine
Molecular Structure
Magnetic Resonance Spectroscopy
Steroids
dioleoyl phosphatidylethanolamine

ASJC Scopus subject areas

  • Biophysics

Cite this

Effect of bile salts on monolayer curvature of a phosphatidylethanolamine/water model membrane system. / Thurmond, R. L.; Lindblom, G.; Brown, Michael F.

In: Biophysical Journal, Vol. 60, No. 3, 1991, p. 728-732.

Research output: Contribution to journalArticle

@article{1ba33dd8d60d41c9a59593f204c62e6a,
title = "Effect of bile salts on monolayer curvature of a phosphatidylethanolamine/water model membrane system",
abstract = "A partial phase diagram of the ternary system dioleoylphosphatidylethanolamine (DOPE)/sodium cholate/water has been determined using 31P Nuclear Magnetic Resonance (NMR) spectroscopy. In the absence of cholate, it is well known that the DOPE/water system forms a reversed hexagonal (H(II)) phase. We have found that addition of even small amounts of cholate to the DOPE/water system leads to a transition to a lamellar (L(α)) phase. At higher cholate concentrations, a cubic (I) phase (low water content) or a micellar solution (L1) phase (high water content) is present. Thus, cholate molecules have a strong tendency to alter the lipid monolayer curvature. Increasing the concentration of cholate changes the curvature of DOPE from negative (H(II) phase), through zero (L(α) phase), and finally to a phase of positive curvature (micellar solution). This observation can be rationalized in terms of the molecular structure of cholate, which is amphipathic and has one hydrophobic and one hydrophilic side of the steroid ring system. The cholate molecules have a tendency to lie flat on the lipid aggregate surface, thereby increasing the effective interfacial area of the polar head groups, and altering the curvature free energy of the system.",
author = "Thurmond, {R. L.} and G. Lindblom and Brown, {Michael F}",
year = "1991",
language = "English (US)",
volume = "60",
pages = "728--732",
journal = "Biophysical Journal",
issn = "0006-3495",
publisher = "Biophysical Society",
number = "3",

}

TY - JOUR

T1 - Effect of bile salts on monolayer curvature of a phosphatidylethanolamine/water model membrane system

AU - Thurmond, R. L.

AU - Lindblom, G.

AU - Brown, Michael F

PY - 1991

Y1 - 1991

N2 - A partial phase diagram of the ternary system dioleoylphosphatidylethanolamine (DOPE)/sodium cholate/water has been determined using 31P Nuclear Magnetic Resonance (NMR) spectroscopy. In the absence of cholate, it is well known that the DOPE/water system forms a reversed hexagonal (H(II)) phase. We have found that addition of even small amounts of cholate to the DOPE/water system leads to a transition to a lamellar (L(α)) phase. At higher cholate concentrations, a cubic (I) phase (low water content) or a micellar solution (L1) phase (high water content) is present. Thus, cholate molecules have a strong tendency to alter the lipid monolayer curvature. Increasing the concentration of cholate changes the curvature of DOPE from negative (H(II) phase), through zero (L(α) phase), and finally to a phase of positive curvature (micellar solution). This observation can be rationalized in terms of the molecular structure of cholate, which is amphipathic and has one hydrophobic and one hydrophilic side of the steroid ring system. The cholate molecules have a tendency to lie flat on the lipid aggregate surface, thereby increasing the effective interfacial area of the polar head groups, and altering the curvature free energy of the system.

AB - A partial phase diagram of the ternary system dioleoylphosphatidylethanolamine (DOPE)/sodium cholate/water has been determined using 31P Nuclear Magnetic Resonance (NMR) spectroscopy. In the absence of cholate, it is well known that the DOPE/water system forms a reversed hexagonal (H(II)) phase. We have found that addition of even small amounts of cholate to the DOPE/water system leads to a transition to a lamellar (L(α)) phase. At higher cholate concentrations, a cubic (I) phase (low water content) or a micellar solution (L1) phase (high water content) is present. Thus, cholate molecules have a strong tendency to alter the lipid monolayer curvature. Increasing the concentration of cholate changes the curvature of DOPE from negative (H(II) phase), through zero (L(α) phase), and finally to a phase of positive curvature (micellar solution). This observation can be rationalized in terms of the molecular structure of cholate, which is amphipathic and has one hydrophobic and one hydrophilic side of the steroid ring system. The cholate molecules have a tendency to lie flat on the lipid aggregate surface, thereby increasing the effective interfacial area of the polar head groups, and altering the curvature free energy of the system.

UR - http://www.scopus.com/inward/record.url?scp=0025942780&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0025942780&partnerID=8YFLogxK

M3 - Article

VL - 60

SP - 728

EP - 732

JO - Biophysical Journal

JF - Biophysical Journal

SN - 0006-3495

IS - 3

ER -