Linked Life Data

17412361

Source:http://linkedlifedata.com/resource/pubmed/id/17412361

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2007-4-30
pubmed:abstractText
Biologically important peptides such as the Alzheimer peptide Abeta(1-40) display a reversible random coil <==>beta-structure transition at anionic membrane surfaces. In contrast to the well-studied random coil left arrow over right arrow alpha-helix transition of amphipathic peptides, there is a dearth on information on the thermodynamic and kinetic parameters of the random coil left arrow over right arrow beta-structure transition. Here, we present a new method to quantitatively analyze the thermodynamic parameters of the membrane-induced beta-structure formation. We have used the model peptide (KIGAKI)(3) and eight analogues in which two adjacent amino acids were substituted by their d-enantiomers. The positions of the d,d pairs were shifted systematically along the three identical segments of the peptide chain. The beta-structure content of the peptides was measured in solution and when bound to anionic lipid membranes with circular dichroism spectroscopy. The thermodynamic binding parameters were determined with isothermal titration calorimetry and the binding isotherms were analysed by combining a surface partition equilibrium with the Gouy-Chapman theory. The thermodynamic parameters were found to be linearly correlated with the extent of beta-structure formation. beta-Structure formation at the membrane surface is characterized by an enthalpy change of DeltaH(beta)=-0.23 kcal/mol per residue, an entropy change of DeltaS(beta)=-0.24 cal/mol K residue and a free energy change of DeltaG(beta)=-0.15 kcal/mol residue. An increase in temperature induces an unfolding of beta-structure. The residual free energy of membrane-induced beta-structure formation is close to that of membrane-induced alpha-helix formation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
369
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
277-89
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Thermodynamics of the coil <==> beta-sheet transition in a membrane environment.
pubmed:affiliation
Department of Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't