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/sup 31/P NMR studies of oriented multilayers formed from isolated sarcoplasmic reticulum and reconstituted sarcoplasmic reticulum: evidence that ''boundary-layer'' phospholipid is not immobilized

Conference · · Biophys. J.; (United States)
OSTI ID:5608219

Studies were made of the angular dependence of the /sup 31/P NMR signal from oriented sarcoplasmic reticulum membranes. Similar spectra were obtained from oriented reconstituted sarcoplasmic reticulum membranes with lipid-to-protein ratios ranging from 42.1 to 110.1 and from oriented bilayer membranes formed from sarcoplasmic reticulum phospholipids. The dependence of the /sup 31/P NMR spectra on the alignment of the membranes with respect to the magnetic field was used to draw two conclusions about the motion of the phospholipid molecules that contribute to the observed spectra. First, the phosphate group and the two adjacent methylene groups are able to rotate rapidly (i.e., faster than 10/sup -5/ s) around the normal to the plane of the membrane. Second, calibration experiments showed that all (100 +/- 7%) of the phospholipid molecules in the membrane can be accounted for in the observed spectra. Thus, essentially all the phospholipid molecules in the sarcoplasmic reticulum and the reconstituted sarcoplasmic reticulum membranes have the same motion in the polar headgroup region as found in model bilayer membranes. (JMT)

OSTI ID:
5608219
Journal Information:
Biophys. J.; (United States), Journal Name: Biophys. J.; (United States) Vol. 37:1; ISSN BIOJA
Country of Publication:
United States
Language:
English