Linked Life Data

19419221

Source:http://linkedlifedata.com/resource/pubmed/id/19419221

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
19
pubmed:dateCreated
2009-5-7
pubmed:abstractText
The involvement of membrane-bound peptides and the influence of protein conformations in several neurodegenerative diseases lead us to analyze the interactions of model peptides with artificial membranes. Two model peptides were selected. The first one, an alanine-rich peptide, K3A18K3, was shown to be in alpha-helix structures in TFE, a membrane environment-mimicking solvent, while it was mostly beta-sheeted in aqueous buffer as revealed by infrared spectroscopy. The other, alamethicin, a natural peptide, was in a stable alpha-helix structure. To determine the role of the peptide conformation on the nature of its interactions with lipids, we compared the structure and topology of the conformational-labile peptide K3A18K3 and of the alpha-helix rigid alamethicin in both aqueous and phospholipid environments (Langmuir monolayers and multilamellar vesicles). K3A18K3 at the air-water interface showed a pressure-dependent orientation of its beta-sheets, while the alpha-helix axis of alamethicin was always parallel to the interface, as probed by polarization modulation infrared reflection absorption spectroscopy. The beta-sheeted K3A18K3 peptide was uniformly distributed into DPPC condensed domains, while the helical-alamethicin insertion distorted the DPPC condensed domains, as evidenced by Brewster angle microscopy imaging of the air/interface. The beta-sheeted K3A18K3 interacted with DMPC multilamellar vesicles via hydrophilic interactions with polar heads and the helical-alamethicin via hydrophobic interactions with alkyl chains, as shown by infrared spectroscopy and solid state NMR. Our findings are consistent with the prevailing assumption that the conformation of the peptide predetermines the mode of interaction with lipids. More precisely, helical peptides tend to be inserted via hydrophobic interactions within the hydrophobic region of membranes, while beta-sheeted peptides are predisposed to interact with polar groups and stay at the surface of lipid layers.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1520-6106
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
113
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7012-9
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Conformational and interfacial analyses of K3A18K3 and alamethicin in model membranes.
pubmed:affiliation
Université de Lyon, INSA de Lyon, and ICBMS CNRS UMR 5246, Villeurbanne, F-69622, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't