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Interactions of native and aggregated HypF‐N with lipid monolayers and supported bilayers of varied lipid composition
Author(s) -
Marano Nadia,
Mackay Fraser,
Nichino Daniela,
Relini Annalisa,
Rolandi Ranieri,
Gliozzi Alessandra,
Stefani Massimo
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.851.5
Subject(s) - membrane , chemistry , liposome , phosphatidylcholine , sphingomyelin , biophysics , lipid bilayer , biochemistry , phospholipid , biology
We studied the effect of the model amyloid‐forming protein, HypF‐N (the N‐terminal domain of the prokaryotic hydrogenase maturation factor HypF), in its native and aggregated form on the integrity of model lipid membranes, including those more representative of natural membranes, using AFM and surface pressure measurements. Using fluorescence spectroscopy, we studied the effect of lipids on the structure of HypF‐N. We find that native protein has a larger effect on model membranes than aggregated protein. Model membranes composed of lipid raft forming mixtures (phosphatidylcholine: sphingomyelin: cholesterol, 1:1:1) were much more resistant to insertion of protein and membrane disruption than those composed of a 1:1 mixture of phosphatidylcholine (PC) and phosphatidylserine (PS). Addition of cholesterol to the latter mixture made the membranes less resistant to protein insertion. Liposomes containing the negatively charged lipid PS induced a strong quenching in fluorescence of HypF‐N (indicating a change in the environment of tryptophan and tyrosine residues) while those containing only PC had little effect. Preliminary denaturation experiments indicate relatively strong binding of HypF‐N to PS:PC liposomes. Research was supported by Saint Lawrence University, University of Genoa and University of Florence.