Disordered binding of small molecules to Aβ(12-28)

TitleDisordered binding of small molecules to Aβ(12-28)
Publication TypeJournal Article
Year of Publication2011
AuthorsConvertino M., Vitalis A., Caflisch A.
JournalThe Journal of Biological Chemistry
Date Published2011 Dec 2
Type of ArticleResearch Article
KeywordsAmyloid beta-Peptides, Humans, Hydrogen-Ion Concentration, Peptide Fragments, Protein Binding, Protein Multimerization, Protein Structure, Secondary

In recent years, an increasing number of small molecules and short peptides have been identified that interfere with aggregation and/or oligomerization of the Alzheimer β-amyloid peptide (Aβ). Many of them possess aromatic moieties, suggesting a dominant role for those in interacting with Aβ along various stages of the aggregation process. In this study, we attempt to elucidate whether interactions of such aromatic inhibitors with monomeric Aβ(12-28) point to a common mechanism of action by performing atomistic molecular dynamics simulations at equilibrium. Our results suggest that, independently of the presence of inhibitors, monomeric Aβ(12-28) populates a partially collapsed ensemble that is largely devoid of canonical secondary structure at 300 K and neutral pH. The small molecules have different affinities for Aβ(12-28) that can be partially rationalized by the balance of aromatic and charged moieties constituting the molecules. There are no predominant binding modes, although aggregation inhibitors preferentially interact with the N-terminal portion of the fragment (residues 13-20). Analysis of the free energy landscape of Aβ(12-28) reveals differences highlighted by altered populations of a looplike conformer in the presence of inhibitors. We conclude that intrinsic disorder of Aβ persists at the level of binding small molecules and that inhibitors can significantly alter properties of monomeric Aβ via multiple routes of differing specificity.



Alternate JournalJ. Biol. Chem.
PubMed ID21969380
PubMed Central IDPMC3308868
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