Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2007-4-20
pubmed:abstractText
Sec14p promotes the energy-independent transfer of either phosphatidylinositol (PtdIns) or phosphatidylcholine (PtdCho) between lipid bilayers in vitro and represents the major PtdIns/PtdCho transfer protein in the budding yeast Saccharomyces cerevisiae. Herein, we employ multi-frequency high-field electron paramagnetic resonance (EPR) to analyze the electrostatic and hydrogen-bonding microenvironments for series of doxyl-labeled PtdCho molecules bound by Sec14p in a soluble protein-PtdCho complex. A structurally similar compound, 5-doxyl stearic acid dissolved in a series of solvents, was used for experimental calibration. The experiments yielded two-component rigid limit 130- and 220-GHz EPR spectra with excellent resolution in the gx region. Those components were assigned to hydrogen-bonded and nonhydrogen-bonded nitroxide species. Partially resolved 130-GHz EPR spectra from n-doxyl-PtdCho bound to Sec14p were analyzed using this two-component model and allowed quantification of two parameters. First, the fraction of hydrogen-bonded nitroxide species for each n-doxyl-PtdCho was calculated. Second, the proticity profile along the phospholipid-binding cavity of Sec14p was characterized. The data suggest the polarity gradient inside the Sec14p cavity is a significant contributor to the driving molecular forces for extracting a phospholipid from the bilayer. Finally, the enhanced g-factor resolution of EPR at 130 and 220 GHz provides researchers with a spectroscopic tool to deconvolute two major contributions to the x-component of the nitroxide g-matrix: hydrogen-bond formation and local electrostatic effects.
pubmed:grant
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/17325006-10648147, http://linkedlifedata.com/resource/pubmed/commentcorrection/17325006-10773169, http://linkedlifedata.com/resource/pubmed/commentcorrection/17325006-12069788, http://linkedlifedata.com/resource/pubmed/commentcorrection/17325006-12885649, http://linkedlifedata.com/resource/pubmed/commentcorrection/17325006-14731807, http://linkedlifedata.com/resource/pubmed/commentcorrection/17325006-15869384, http://linkedlifedata.com/resource/pubmed/commentcorrection/17325006-16455519, http://linkedlifedata.com/resource/pubmed/commentcorrection/17325006-4351059, http://linkedlifedata.com/resource/pubmed/commentcorrection/17325006-4366085, http://linkedlifedata.com/resource/pubmed/commentcorrection/17325006-7518705, http://linkedlifedata.com/resource/pubmed/commentcorrection/17325006-7647239, http://linkedlifedata.com/resource/pubmed/commentcorrection/17325006-9461221
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-3495
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
92
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3686-95
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Local polarity and hydrogen bonding inside the Sec14p phospholipid-binding cavity: high-field multi-frequency electron paramagnetic resonance studies.
pubmed:affiliation
Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA. Tatyana_Smirnova@ncsu.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural