Abstract
THE structure and orientation of the phosphocholine polar group in lecithin-containing membranes has been discussed extensively. Studies of egg-yolk lecithin and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), using neutron diffraction and 2H and 31P nuclear magnetic resonance (NMR), have led to the conclusion that the phosphocholine dipole is orientated parallel to the membrane surface1-4. On the other hand, 1H and 31P NMR spectra of sonicated DPPC vesicles in the presence of trivalent ions suggested that the choline group is extended approximately perpendicular5 or folded parallel6 to the bilayer surface. We have, therefore, repeated our previous 2H and 31P NMR measurements in the presence of trivalent ions and report here that the addition of these shift reagents induces large changes in the spectral parameters, that is, the 2H quadrupole splittings and the 31P chemical shift anisotropy. These observations can only be interpreted in terms of specific ion-induced changes in the choline head group conformation of DPPC.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 721-723 |
| Number of pages | 3 |
| Journal | Nature |
| Volume | 269 |
| Issue number | 5630 |
| DOIs | |
| State | Published - 1977 |
| Externally published | Yes |
Fingerprint
ASJC Scopus subject areas
- General
Cite this
Ion-induced changes in head group conformation of lecithin bilayers. / Brown, Michael F; Seelig, Joachim.
In: Nature, Vol. 269, No. 5630, 1977, p. 721-723.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Ion-induced changes in head group conformation of lecithin bilayers
AU - Brown, Michael F
AU - Seelig, Joachim
PY - 1977
Y1 - 1977
N2 - THE structure and orientation of the phosphocholine polar group in lecithin-containing membranes has been discussed extensively. Studies of egg-yolk lecithin and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), using neutron diffraction and 2H and 31P nuclear magnetic resonance (NMR), have led to the conclusion that the phosphocholine dipole is orientated parallel to the membrane surface1-4. On the other hand, 1H and 31P NMR spectra of sonicated DPPC vesicles in the presence of trivalent ions suggested that the choline group is extended approximately perpendicular5 or folded parallel6 to the bilayer surface. We have, therefore, repeated our previous 2H and 31P NMR measurements in the presence of trivalent ions and report here that the addition of these shift reagents induces large changes in the spectral parameters, that is, the 2H quadrupole splittings and the 31P chemical shift anisotropy. These observations can only be interpreted in terms of specific ion-induced changes in the choline head group conformation of DPPC.
AB - THE structure and orientation of the phosphocholine polar group in lecithin-containing membranes has been discussed extensively. Studies of egg-yolk lecithin and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), using neutron diffraction and 2H and 31P nuclear magnetic resonance (NMR), have led to the conclusion that the phosphocholine dipole is orientated parallel to the membrane surface1-4. On the other hand, 1H and 31P NMR spectra of sonicated DPPC vesicles in the presence of trivalent ions suggested that the choline group is extended approximately perpendicular5 or folded parallel6 to the bilayer surface. We have, therefore, repeated our previous 2H and 31P NMR measurements in the presence of trivalent ions and report here that the addition of these shift reagents induces large changes in the spectral parameters, that is, the 2H quadrupole splittings and the 31P chemical shift anisotropy. These observations can only be interpreted in terms of specific ion-induced changes in the choline head group conformation of DPPC.
UR - http://www.scopus.com/inward/record.url?scp=0017672468&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0017672468&partnerID=8YFLogxK
U2 - 10.1038/269721a0
DO - 10.1038/269721a0
M3 - Article
AN - SCOPUS:0017672468
VL - 269
SP - 721
EP - 723
JO - Nature
JF - Nature
SN - 0028-0836
IS - 5630
ER -