Thermodynamic Studies of Macromolecular Models
Author
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