Document Detail

The promiscuous protein binding ability of erythrosine B studied by metachromasy (metachromasia).
MedLine Citation:
PMID:  23456742     Owner:  NLM     Status:  MEDLINE    
The present study aims to elucidate aspects of the protein binding ability of erythrosine B (ErB), a poly-iodinated xanthene dye and an FDA-approved food colorant (FD&C Red No. 3), which we have identified recently as a promiscuous inhibitor of protein-protein interactions (PPIs) with a remarkably consistent median inhibitory concentration (IC50 ) in the 5- to 30-μM range. Because ErB exhibits metachromasy, that is, color change upon binding to several proteins, we exploited this property to quantify its binding to proteins such as bovine serum albumin (BSA) and CD40L (CD154) and to determine the corresponding binding constants (Kd ) and stoichiometry (nb ) using spectrophotometric methods. Binding was reversible, and the estimated affinities for both protein targets obtained here (Kd values of 14 and 20 μM for BSA and CD40L, respectively) were in good agreement with that expected from the PPI inhibitory activity of ErB. A stoichiometry greater than one was observed both for CD40L and BSA binding (nb of 5-6 and 8-9 for BSA and CD40L, respectively), indicating the possibility of nonspecific binding of the flat and rigid ErB molecule at multiple sites, which could explain the promiscuous PPI inhibitory activity if some of these overlap with the binding site of the protein partner and interfere with the binding.
Lakshmi Ganesan; Peter Buchwald
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural    
Journal Detail:
Title:  Journal of molecular recognition : JMR     Volume:  26     ISSN:  1099-1352     ISO Abbreviation:  J. Mol. Recognit.     Publication Date:  2013 Apr 
Date Detail:
Created Date:  2013-03-04     Completed Date:  2013-08-09     Revised Date:  2014-04-03    
Medline Journal Info:
Nlm Unique ID:  9004580     Medline TA:  J Mol Recognit     Country:  England    
Other Details:
Languages:  eng     Pagination:  181-9     Citation Subset:  IM    
Copyright Information:
Copyright © 2013 John Wiley & Sons, Ltd.
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MeSH Terms
CD40 Ligand / chemistry
Erythrosine / chemistry*
Food Coloring Agents / chemistry*
Protein Binding
Serum Albumin, Bovine / chemistry
Spectrum Analysis
Grant Support
Reg. No./Substance:
0/Food Coloring Agents; 0/Serum Albumin, Bovine; 147205-72-9/CD40 Ligand; PN2ZH5LOQY/Erythrosine

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