Document Detail

Effect of association with sulfate on the electrophoretic mobility of polyarginine and polylysine.
MedLine Citation:
PMID:  20726540     Owner:  NLM     Status:  MEDLINE    
Domains rich in cationic amino acids are ubiquitous in peptides with the ability to cross cell membranes, which is likely related to the binding of such polypeptides to anionic groups on the membrane surface. To shed more light on these interactions, we investigated specific interactions between basic amino acids and oligopeptides thereof and anions by means of electrophoretic experiments and molecular dynamics simulations. To this end, we measured the electrophoretic mobilities of arginine, lysine, tetraarginine, and tetralysine in sodium chloride and sodium sulfate electrolytes as a function of ionic strength. The mobility was found to be consistently lower in sodium sulfate than in sodium chloride at the same ionic strength. The decrease in mobility in sodium sulfate was greater for tetraarginine than for tetralysine and was larger for tetrapeptides compared to the corresponding free amino acids. On the basis of molecular dynamics simulations and Bjerrum theory, we rationalize these results in terms of enhanced association between the amino acid side chains and sulfate. Simulations also predict a greater affinity of sulfate to the guanidinium side chain groups of arginine than to the ammonium groups of lysine, as the planar guanidinium geometry allows simultaneous strong hydrogen bonding to two sulfate oxygens. We show that the sulfate binding to arginine, but not to lysine, is cooperative. These results are consistent with the greater decrease in the mobility of arginine compared to that of lysine upon addition of sulfate salt. The nonspecific mobility retardation by sulfate is ascribed to its electrostatic interaction with the cationic amino acid side chain groups.
Erik Wernersson; Jan Heyda; Anna Kubícková; Tomás Krízek; Pavel Coufal; Pavel Jungwirth
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The journal of physical chemistry. B     Volume:  114     ISSN:  1520-5207     ISO Abbreviation:  J Phys Chem B     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-09-09     Completed Date:  2011-01-12     Revised Date:  2013-01-24    
Medline Journal Info:
Nlm Unique ID:  101157530     Medline TA:  J Phys Chem B     Country:  United States    
Other Details:
Languages:  eng     Pagination:  11934-41     Citation Subset:  IM    
Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, and Center for Biomolecules and Complex Molecular Systems, Flemingovo nám. 2, 16610 Prague 6, Czech Republic.
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MeSH Terms
Electrophoresis / methods*
Guanidine / chemistry
Ions / chemistry*
Models, Molecular
Molecular Dynamics Simulation*
Osmolar Concentration
Peptides / chemistry*,  genetics
Polylysine / chemistry*
Sodium Chloride / chemistry
Sulfates / chemistry*
Reg. No./Substance:
0/Ions; 0/Peptides; 0/Sulfates; 0YPR65R21J/sodium sulfate; 113-00-8/Guanidine; 25104-18-1/Polylysine; 25212-18-4/polyarginine; 7647-14-5/Sodium Chloride

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