Linked Life Data

2163285

Source:http://linkedlifedata.com/resource/pubmed/id/2163285

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1990-8-8
pubmed:abstractText
By varying the pH, the influence of the ionization degree on the structure and dynamics of aqueous dispersions of 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS) was studied, using 2H-NMR methods. For this purpose DOPS was synthesized with deuterium labels incorporated either stereospecifically at the beta-position of the serine headgroup ([2-2H]DOPS) or at the 11-position of both acyl chains ([11,11-2H2]DOPS), allowing the effects of pH on headgroup and acyl chains to be measured in parallel. A large scale synthesis procedure of stereospecific 1,2-dioleoyl-sn-glycero-3-phospho-[2-2H]-L- serine is described. The quadrupolar splitting (delta nu q) of [2-2H]DOPS is shown to be a sensitive sensor for the degree of protonation of the molecule. Whereas the delta nu q of [2-2H]DOPS decreases upon lowering the pH, that of [11,11-2H2]DOPS gradually increases, indicating an increase in acyl chain ordering. In the pH range below the pKa value, DOPS exhibits a temperature-dependent bilayer to hexagonal HII phase transition, apparent from the 31P-NMR spectra and the occurrence of a second component in the [11,11-2H2]DOPS 2H-NMR spectrum, with a much smaller delta nu q. The HII phase component in spectra from [2-2H]DOPS coincides with the isotropic position and has no defined delta nu q. In the bilayer organization delta nu q and spin-lattice relaxation time (T1) values for the acyl chain deuterated DOPS are similar to those obtained for other lipid systems. In contrast the PS headgroup region displays a relatively rigid structure as evidenced by a large delta nu q and very small T1 values. Upon adopting the HII phase the T1 values of the acyl chain deuterons are hardly affected. The uniqueness of the PS headgroup with respect to structure and motional properties is reinforced by the occurrence of a T1 minimum at 45 degrees C in the measurement of the temperature dependence of T1 for [2-2H]DOPS in the hexagonal HII configuration. Quantitative analysis yields a correlation time (tau c) for the motions determining T1 under these conditions, of 3.45 ns.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0009-3084
pubmed:author
pubmed:issnType
Print
pubmed:volume
54
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
33-42
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
The pH dependence of headgroup and acyl chain structure and dynamics of phosphatidylserine, studied by 2H-NMR.
pubmed:affiliation
Centre for Biomembranes and Lipid Enzymology, University of Utrecht, The Netherlands.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't