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High‐resolution NMR studies of the zinc‐binding site of the Alzheimer's amyloid β‐peptide
Author(s) -
Danielsson Jens,
Pierattelli Roberta,
Banci Lucia,
Gräslund Astrid
Publication year - 2007
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2006.05563.x
Subject(s) - chemistry , peptide , binding site , zinc , amyloid beta , dissociation constant , heteronuclear molecule , metal , stereochemistry , nuclear magnetic resonance spectroscopy , biochemistry , receptor , organic chemistry
Metal binding to the amyloid β‐peptide is suggested to be involved in the pathogenesis of Alzheimer's disease. We used high‐resolution NMR to study zinc binding to amyloid β‐peptide 1–40 at physiologic pH. Metal binding induces a structural change in the peptide, which is in chemical exchange on an intermediate rate, between the apo‐form and the holo‐form, with respect to the NMR timescale. This causes loss of NMR signals in the resonances affected by the binding. Heteronuclear correlation experiments, 15 N‐relaxation and amide proton exchange experiments on amyloid β‐peptide 1–40 revealed that zinc binding involves the three histidines (residues 6, 13 and 14) and the N‐terminus, similar to a previously proposed copper‐binding site [Syme CD, Nadal RC, Rigby SE, Viles JH (2004) J Biol Chem 279 , 18169–18177]. Fluorescence experiments show that zinc shares a common binding site with copper and that the metals have similar affinities for amyloid β‐peptide. The dissociation constant K d of zinc for the fragment amyloid β‐peptide 1–28 was measured by fluorescence, using competitive binding studies, and that for amyloid β‐peptide 1–40 was measured by NMR. Both methods gave K d values in the micromolar range at pH 7.2 and 286 K. Zinc also has a second, weaker binding site involving residues between 23 and 28. At high metal ion concentrations, the metal‐induced aggregation should mainly have an electrostatic origin from decreased repulsion between peptides. At low metal ion concentrations, on the other hand, the metal‐induced structure of the peptide counteracts aggregation.