Peptide secondary structure induced by a micellar phospholipidic interface: proton NMR conformational study of a lipopeptide. |
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Authors: | F Macquaire F Baleux E Giaccobi T Huynh-Dinh J M Neumann A Sanson |
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Institution: | Département de Biologie Cellulaire et Moléculaire, SBPM, URA CNRS 1290, Gif sur Yvette, France. |
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Abstract: | The conformational change of the model peptide Ac-K-G-R-G-D-G-amide induced by a phospholipidic interface was investigated by proton nuclear magnetic resonance (1H NMR). In aqueous solution, the free peptide is highly flexible and disordered, even in the presence of deuterated dodecyl-phosphocholine (DPC-d38) micelles which mimic a membrane interface. The lipopeptide, obtained by grafting a lipid anchor 2,3-dipalmitoyl-D-(+)-glyceric acid] to the lysine side chain of the peptide, was studied by standard 2D 1H NMR spectroscopy combined with distance geometry and simulated annealing calculations. When anchored to a micelle interface, the peptide acquires a definite turn (II/I') conformation. We were also able to describe precisely the conformation of the diacylglyceric fragment of the lipopeptide in a lipid environment and to establish the average orientation of the peptide segment with respect to the micelle surface. |
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