Molecular Insights into Dipole Relaxation Processes in Water-Lysine Mixtures
Artikel i vetenskaplig tidskrift, 2019

Dielectric spectroscopy is a robust method to investigate relaxations of molecular dipoles. It is particularly useful for studies of biological solutions because of the potential of this method to cover a broad range of dynamical time scales typical for such systems. However, this technique does not provide any information about the nature of the molecular motions, which leads to a certain underemployment of dielectric spectroscopy for gaining microscopic understanding of material properties. For such detailed understanding, computer simulations are valuable tools because they can provide information about the nature of molecular motions observed by, for example, dielectric spectroscopy and to further complement them with structural information. In this work, we acquire information about the nature of dipole relaxation, in n-lysine solutions by means of molecular dynamics simulations. Our results indicate that the experimentally observed main relaxation process of n-lysine has different origins for the single monomer and the polypeptide chains. The relaxation of 1-lysine is due to the motions of whole molecules, whereas the experimentally observed relaxation of 3-lysine and 4-lysine is due to the motions of the residues, which, in turn, are promoted by water relaxation. Furthermore, we propose a new structural model of the lysine amino acids, which can quantitatively account for the experimental dielectric relaxation data. Hydrogen bonding and the structure of water are also discussed in terms of their influence on relaxation processes.

Författare

Alexandr Nasedkin

Chalmers, Fysik, Biologisk fysik

Silvina Cerveny

DIPC

Universidad del Pais Vasco/ Euskal Herriko Unibertsitatea

Jan Swenson

Chalmers, Fysik, Biologisk fysik

Journal of Physical Chemistry B

1520-6106 (ISSN) 1520-5207 (eISSN)

Vol. 123 28 6056-6064

Ämneskategorier

Fysikalisk kemi

Biofysik

DOI

10.1021/acs.jpcb.9b01928

PubMed

31268322

Mer information

Senast uppdaterat

2020-07-31