The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Thermodynamic Studies of Macromolecular Models

På svenska

Author

  • Ola Sommelius

Summary, in English

The thermodynamic properties of single chain polyelectrolyte and protein models are studied using Monte Carlo simulations and (for the polyelectrolyte models) variational calculations and high- and low-temperature expansions. A variational method is used for minimizing Lennard-Jones energies and for estimating end-to-end distances for a rigid Coulomb chain at finite temperatures. A polyelectrolyte chain is viewed as Gaussian chain augmented with a Coulomb or screened Coulomb (Debye-Huckel) interaction between all pairs of monomers. Variational calculations are also used together with Monte Carlo simulations to study the behavior of a titrating polyelectrolyte. Furthermore a method for mapping the original polymer to a smaller one by introducing a corrective nearest-neighbor interaction is presented. The underlying assumptions for this approach is examined using high- and low-temperature expansions. The effect of the screening length on the stiffness, defined by the persistence length, of a screened Coulomb chain is studied. Moreover a three dimensional off-lattice model for protein folding is presented. The model has two types of residues, hydrophobic and hydrophilic respectively, that interact via a sequence dependent Lennard-Jones potential. The influence of sequence independent local interactions is studied as well as the folding properties and the formation of the native state.

Publishing year

1997

Language

English

Document type

Dissertation

Publisher

Department of Theoretical Physics, Lund University

Topic

  • Biophysics

Keywords

  • classical mechanics
  • Mathematical and general theoretical physics
  • termodynamik
  • klassisk mekanik
  • Matematisk och allmän teoretisk fysik
  • statistisk fysik
  • gravitation
  • kvantmekanik
  • relativitet
  • quantum mechanics
  • relativity
  • statistical physics
  • thermodynamics
  • Fysicumarkivet A:1997:Sommelius

Status

Published

Supervisor

  • [unknown] [unknown]

ISBN/ISSN/Other

  • ISBN: 91-628-2546-1
  • ISRN: LUNFD6/(NFTF-1033)/1-15/(1997)

Defence date

29 May 1997

Defence time

10:15

Defence place

Auditorium, Dept. of Theoretical Physics

Opponent

  • Enzo Marinari