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1H and 15N NMR characterization of free and bound states of an amphiphilic peptide interacting with calmodulin.

Abstract : A peptide of 17 amino acid residues Ac-L-K-W-K-K-L-L-K-L-L-K-K-L-L-K-L-G-NH2, designed to form an amphiphilic basic alpha-helix [DeGrado, W.F., Prendergast, F. G., Wolfe, H. R., Jr., & Cox, J. A. (1985) J. Cell. Biochem. 29, 83-93], was labeled with 15N at positions 1, 7, 9, and 10. Homo- and heteronuclear NMR techniques were used to characterize the conformational changes of the peptide when it binds to calmodulin in the presence of Ca2+ ions. The spectrum of the free peptide in aqueous solution at pH 6.3 and 298 K was completely assigned by a combined application of several two-dimensional proton NMR methods. Analysis of the short- and medium-range NOE connectivities and of the secondary chemical shifts indicated that the peptide populates, to a significant extent, an alpha-helix conformational state, in agreement with circular dichroism measurements under similar physicochemical conditions. 15N-edited 1D spectra and 15N(omega 2)-half-filtered two-dimensional NMR experiments on the peptide in a 1:1 complex with calmodulin allowed assignment of half of the amide proton resonances and three C alpha H resonances of the bound peptide. The observed NOE connectivities between the peptide backbone protons are indicative of a stable helical secondary structure spanning at least the fragment L1-K11. The equilibrium and dynamic NMR parameters of the bound peptide are discussed in terms of a molecular interaction model.
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https://hal-pasteur.archives-ouvertes.fr/pasteur-00167094
Contributor : Hélène Munier-Lehmann <>
Submitted on : Tuesday, August 14, 2007 - 4:23:08 PM
Last modification on : Tuesday, July 21, 2020 - 3:59:20 AM

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  • HAL Id : pasteur-00167094, version 1
  • PUBMED : 1731872

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B. Prêcheur, Hélène Munier, Joël Mispelter, O. Bârzu, Constantin Craescu. 1H and 15N NMR characterization of free and bound states of an amphiphilic peptide interacting with calmodulin.. Biochemistry, American Chemical Society, 1992, 31 (1), pp.229-36. ⟨pasteur-00167094⟩

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