Methylations of tryptophan-modified naphthoquinone affect its inhibitory potential toward Aβ aggregation

TitleMethylations of tryptophan-modified naphthoquinone affect its inhibitory potential toward Aβ aggregation
Publication TypeJournal Article
Year of Publication2013
AuthorsScherzer-Attali R., Convertino M., Pellarin R., Gazit E., Segal D., Caflisch A.
JournalThe Journal of Physical Chemistry B
Volume117
Issue6
Pagination1780-1789
Date Published2013 Feb 14
Type of ArticleResearch Article
ISSN1520-5207
KeywordsAlzheimer Disease, Amyloid beta-Peptides, Fluorescence Polarization, Humans, Hydrogen Bonding, Molecular Dynamics Simulation, Naphthoquinones, Peptide Fragments, Structure-Activity Relationship, Tryptophan
Abstract

Aggregation of amyloid beta (Aβ) is the hallmark of Alzheimer's disease (AD). Small molecules inhibiting Aβ can be valuable therapeutics for AD. We have previously reported that 1,4-naphthoquinon-2-yl-l-tryptophan (NQTrp), reduces aggregation and oligomerization of Aβ in vitro and in vivo. In silico analysis further showed that certain functional groups of NQTrp, not in the aromatic rings, are also involved in binding and inhibiting Aβ. To better understand the exact mode of action and identify the groups crucial for NQTrp inhibitory activity, we conducted structure-activity analysis. Four derivatives of NQTrp were studied in silico: a D-isomer, two single-methylated and one double-methylated derivative. In silico results showed that the NQTrp groups involved in hydrogen bonds are the anilinic NH (i.e., the NH linker between the quinone and tryptophan moieties), the quinonic carbonyls, and the carboxylic acid. These predictions were supported by in vitro results. Our results should aid in designing improved small-molecule inhibitors of Aβ aggregation for treating AD.

DOI10.1021/jp309066p
pubindex

0169

Alternate JournalJ. Phys. Chem. B
PubMed ID23259849