Journal
JOURNAL OF PHYSICAL CHEMISTRY B
Volume 114, Issue 36, Pages 11934-11941Publisher
AMER CHEMICAL SOC
DOI: 10.1021/jp1054342
Keywords
-
Categories
Funding
- Czech Ministry of Education [LC512, MSM0021620857]
- Czech Science Foundation [203/08/0114]
- Grant Agency of the Charles University [SVV 261204]
- Academy of Sciences [Z40550506]
- International Max-Planck Research School
Ask authors/readers for more resources
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.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available