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Title: A molecular view of the role of chirality in charge-driven polypeptide complexation

Abstract

Polyelectrolyte molecules of opposite charge are known to form stable complexes in solution. Depending on the system conditions, such complexes can be solid or liquid. The latter are known as complex coacervates, and they appear as a second liquid phase in equilibrium with a polymer-dilute aqueous phase. This work considers the complexation between poly(glutamic acid) and poly(lysine), which is of particular interest because it enables examination of the role of chirality in ionic complexation, without changes to the overall chemical composition. Systematic atomic-level simulations are carried out for chains of poly(glutamic acid) and poly(lysine) with varying combinations of chirality along the backbone. Achiral chains form unstructured complexes. In contrast, homochiral chains lead to formation of stable beta-sheets between molecules of opposite charge, and experiments indicate that beta-sheet formation is correlated with the formation of solid precipitates. Changes in chirality along the peptide backbone are found to cause "kinks" in the beta-sheets. These are energetically unfavorable and result in irregular structures that are more difficult to pack together. Taken together, these results provide new insights that may be of use for the development of simple yet strong bioinspired materials consisting of beta-rich domains and amorphous regions.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division; National Institute of Standards and Technology (NIST)
OSTI Identifier:
1352834
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Soft Matter; Journal Volume: 11; Journal Issue: 8
Country of Publication:
United States
Language:
English

Citation Formats

Hoffmann, K. Q., Perry, S. L., Leon, L., Priftis, D., Tirrell, M., and de Pablo, J. J. A molecular view of the role of chirality in charge-driven polypeptide complexation. United States: N. p., 2015. Web. doi:10.1039/c4sm02336f.
Hoffmann, K. Q., Perry, S. L., Leon, L., Priftis, D., Tirrell, M., & de Pablo, J. J. A molecular view of the role of chirality in charge-driven polypeptide complexation. United States. doi:10.1039/c4sm02336f.
Hoffmann, K. Q., Perry, S. L., Leon, L., Priftis, D., Tirrell, M., and de Pablo, J. J. Thu . "A molecular view of the role of chirality in charge-driven polypeptide complexation". United States. doi:10.1039/c4sm02336f.
@article{osti_1352834,
title = {A molecular view of the role of chirality in charge-driven polypeptide complexation},
author = {Hoffmann, K. Q. and Perry, S. L. and Leon, L. and Priftis, D. and Tirrell, M. and de Pablo, J. J.},
abstractNote = {Polyelectrolyte molecules of opposite charge are known to form stable complexes in solution. Depending on the system conditions, such complexes can be solid or liquid. The latter are known as complex coacervates, and they appear as a second liquid phase in equilibrium with a polymer-dilute aqueous phase. This work considers the complexation between poly(glutamic acid) and poly(lysine), which is of particular interest because it enables examination of the role of chirality in ionic complexation, without changes to the overall chemical composition. Systematic atomic-level simulations are carried out for chains of poly(glutamic acid) and poly(lysine) with varying combinations of chirality along the backbone. Achiral chains form unstructured complexes. In contrast, homochiral chains lead to formation of stable beta-sheets between molecules of opposite charge, and experiments indicate that beta-sheet formation is correlated with the formation of solid precipitates. Changes in chirality along the peptide backbone are found to cause "kinks" in the beta-sheets. These are energetically unfavorable and result in irregular structures that are more difficult to pack together. Taken together, these results provide new insights that may be of use for the development of simple yet strong bioinspired materials consisting of beta-rich domains and amorphous regions.},
doi = {10.1039/c4sm02336f},
journal = {Soft Matter},
number = 8,
volume = 11,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 2015},
month = {Thu Jan 01 00:00:00 EST 2015}
}