Linked Life Data

15198596

Source:http://linkedlifedata.com/resource/pubmed/id/15198596

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
24
pubmed:dateCreated
2004-6-16
pubmed:abstractText
The lateral membrane organization and phase behavior of the lipid mixture DMPC(di-C(14))/DSPC(di-C(18))/cholesterol (0-33 mol %) with and without an incorporated fluorescence-labeled palmitoyl/farnesyl dual-lipidated peptide, BODIPY-Gly-Cys(Pal)-Met-Gly-Leu-Pro-Cys(Far)-OMe, which represents a membrane recognition model system for Ras proteins, was studied by two-photon excitation fluorescence microscopy. Measurements were performed on giant unilamellar vesicles (GUVs) over a large temperature range, ranging from 30 to 80 degrees C to cover different lipid phase states (all-gel, fluid/gel, liquid-ordered, all-fluid). At temperatures where the fluid-gel coexistence region of the pure binary phospholipid system occurs, large-scale concentration fluctuations appear. Incorporation of cholesterol levels up to 33 mol % leads to a significant increase of conformational order in the membrane system and a reduction of large domain structures. Adding the peptide leads to dramatic changes in the lateral organization of the membrane. With cholesterol present, a phase separation is induced by a lipid sorting mechanism owing to the high affinity of the lipidated peptide to a fluid, DMPC-rich environment. This phase separation leads to the formation of peptide-containing domains with high fluorescence intensity that become progressively smaller with decreasing temperature. As a result, the local concentration of the peptide increases steadily within the confines of the shrinking domains. At the lowest temperatures, where the acyl-chain order parameter of the membrane has already drastically increased and the membrane achieves a liquid-ordered character, an efficient lipid sorting mechanism is no longer supported and aggregation of the peptide into small clusters prevails. We can conclude that palmitoyl/farnesyl dual-lipidated peptides do not associate with liquid-ordered or gel-like domains in phase-separated bilayer membranes. In particular, the study shows the interesting ability of the peptide to induce formation of fluid microdomains at physiologically relevant cholesterol concentrations, and this effect very much depends on the concentration of fluid vs ordered lipid molecules.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0002-7863
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
126
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7496-503
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Partitioning of dual-lipidated peptides into membrane microdomains: lipid sorting vs peptide aggregation.
pubmed:affiliation
Department of Chemistry, Physical Chemistry I, University of Dortmund, Otto-Hahn-Strasse 6, D-44227 Dortmund, Germany.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't