当前位置： SCI文献检索 > BIOPHYSICAL JOURNAL期刊下所有文献 > The diversity of the liquid ordered (Lo) phase of phosphatidylcholine/cholesterol membranes: a variable temperature multinuclear solid-state NMR and x-ray diffraction study.

The diversity of the liquid ordered (Lo) phase of phosphatidylcholine/cholesterol membranes: a variable temperature multinuclear solid-state NMR and x-ray diffraction study.

Abstract：

:To investigate the properties of a pure liquid ordered (Lo) phase in a model membrane system, a series of saturated phosphatidylcholines combined with cholesterol were examined by variable temperature multinuclear (1H, 2H, 13C, 31P) solid-state NMR spectroscopy and x-ray scattering. Compositions with cholesterol concentrations>or=40 mol %, well within the Lo phase region, are shown to exhibit changes in properties as a function of temperature and cholesterol content. The 2H-NMR data of both cholesterol and phospholipids were used to more accurately map the Lo phase boundary. It has been established that the gel-Lo phase coexistence extends to 60 mol % cholesterol and a modified phase diagram is presented. Combined 1H-, 2H-, 13C-NMR, and x-ray scattering data indicate that there are large changes within the Lo phase region, in particular, 1H-magic angle spinning NMR and wide-angle x-ray scattering were used to examine the in-plane intermolecular spacing, which approaches that of a fluid Lalpha phase at high temperature and high cholesterol concentrations. Although it is well known for cholesterol to broaden the gel-to-fluid transition temperature, we have observed, from the 13C magic angle spinning NMR data, that the glycerol region can still undergo a "melting", though this is broadened with increasing cholesterol content and changes with phospholipid chain length. Also from 2H-NMR order parameter data it was observed that the effect of temperature on chain length became smaller with increasing cholesterol content. Finally, from the cholesterol order parameter, it has been previously suggested that it is possible to determine the degree to which cholesterol associates with different phospholipids. However, we have found that by taking into account the relative temperature above the phase boundary this relationship may not be correct.

journal_name

Biophys J

journal_title

Biophysical journal

authors

Clarke JA,Heron AJ,Seddon JM,Law RV

doi

10.1529/biophysj.104.056499

subject

Has Abstract

pub_date

2006-04-01 00:00:00

pages

2383-93

issue

eissn

0006-3495

issn

1542-0086

pii

S0006-3495(06)72421-3

journal_volume

pub_type

杂志文章

在线工具

The diversity of the liquid ordered (Lo) phase of phosphatidylcholine/cholesterol membranes: a variable temperature multinuclear solid-state NMR and x-ray diffraction study.