Document Detail


Lateral diffusion of PEG-Lipid in magnetically aligned bicelles measured using stimulated echo pulsed field gradient 1H NMR.
MedLine Citation:
PMID:  15475584     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Lateral diffusion measurements of PEG-lipid incorporated into magnetically aligned bicelles are demonstrated using stimulated echo (STE) pulsed field gradient (PFG) proton (1H) nuclear magnetic resonance (NMR) spectroscopy. Bicelles were composed of dimyristoyl phosphatidylcholine (DMPC) plus dihexanoyl phosphatidylcholine (DHPC) (q = DMPC/DHPC molar ratio = 4.5) plus 1 mol % (relative to DMPC) dimyristoyl phosphatidylethanolamine-N-[methoxy(polyethylene glycol)-2000] (DMPE-PEG 2000) at 25 wt % lipid. 1H NMR STE spectra of perpendicular aligned bicelles contained only resonances assigned to residual HDO and to overlapping contributions from a DMPE-PEG 2000 ethoxy headgroup plus DHPC choline methyl protons. Decay of the latter's STE intensity in the STE PFG 1H NMR experiment (g(z) = 244 G cm(-1)) yielded a DMPE-PEG 2000 (1 mol %, 35 degrees C) lateral diffusion coefficient D = 1.35 x 10(-11) m2 s(-1). Hence, below the "mushroom-to-brush" transition, DMPE-PEG 2000 lateral diffusion is dictated by its DMPE hydrophobic anchor. D was independent of the diffusion time, indicating unrestricted lateral diffusion over root mean-square diffusion distances of microns, supporting the "perforated lamellae" model of bicelle structure under these conditions. Overall, the results demonstrate the feasibility of lateral diffusion measurements in magnetically aligned bicelles using the STE PFG NMR technique.
Authors:
Ronald Soong; Peter M Macdonald
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2004-10-08
Journal Detail:
Title:  Biophysical journal     Volume:  88     ISSN:  0006-3495     ISO Abbreviation:  Biophys. J.     Publication Date:  2005 Jan 
Date Detail:
Created Date:  2005-01-05     Completed Date:  2005-07-11     Revised Date:  2013-06-09    
Medline Journal Info:
Nlm Unique ID:  0370626     Medline TA:  Biophys J     Country:  United States    
Other Details:
Languages:  eng     Pagination:  255-68     Citation Subset:  IM    
Affiliation:
Department of Chemistry, University of Toronto, Ontario, Canada.
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MeSH Terms
Descriptor/Qualifier:
Biophysics / methods*
Cell Membrane / metabolism
Diffusion
Dimyristoylphosphatidylcholine / chemistry*
Kinetics
Lipids / chemistry
Magnetic Resonance Spectroscopy / methods*
Micelles
Models, Biological
Models, Molecular
Phosphatidylethanolamines / chemistry*
Phospholipid Ethers / chemistry*
Polyethylene Glycols / chemistry*
Protons
Spectrophotometry
Temperature
Time Factors
Chemical
Reg. No./Substance:
0/1,2-dihexadecyl-sn-glycero-3-phosphocholine; 0/Lipids; 0/Micelles; 0/Phosphatidylethanolamines; 0/Phospholipid Ethers; 0/Polyethylene Glycols; 0/Protons; 13699-48-4/Dimyristoylphosphatidylcholine; 20255-95-2/1,2-dimyristoylphosphatidylethanolamine
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