| dc.contributor.advisor | Müller, Marcus Prof. Dr. | de |
| dc.contributor.author | Marelli, Giovanni | de |
| dc.date.accessioned | 2013-02-01T10:57:25Z | de |
| dc.date.available | 2013-02-01T10:57:25Z | de |
| dc.date.issued | 2013-02-01 | de |
| dc.identifier.uri | http://hdl.handle.net/11858/00-1735-0000-000D-F28E-0 | de |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-3698 | |
| dc.language.iso | eng | de |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/3.0/ | |
| dc.subject.ddc | 530 | de |
| dc.title | Minimal models for lipid membranes: local modifications around fusion objects | de |
| dc.type | doctoralThesis | de |
| dc.contributor.referee | Müller, Marcus Prof. Dr. | de |
| dc.date.examination | 2013-01-21 | de |
| dc.subject.gok | Physik (PPN621336750) | de |
| dc.description.abstracteng | Solvent-free soft coarse-grained models are particularly appropriate to investigate collective
phenomena in lipid membranes. In this work we exploit such a model to
show how modifying a few model parameters we can control the bending rigidity of
the membrane, the hydration repulsion, and the macroscopic phases of self-assembled
structures. Further, we investigate the lipid mediated interactions between fusion objects:
transmembrane proteins, pores and stalks. The presence of such defects induces
a perturbation in the shape of the membrane and in the conformations of lipids. The
modi cations induced by single defects superimpose and for some defect interaction
(peptide-peptide, pore-peptide) we identify the equilibrium distance between these objects.
The prediction of the results of the simulations are compared with the numerical
solution of a continuum model parametrized from the analysis of the simulation snapshots.
The presence of transmembrane proteins with a large hydrophobic mismatch weakens
the membrane over the direct interaction range decreasing slightly the membrane
thickness. This involves the lowering of the line tension of the pore and for a particular
number and spatial arrangement of proteins the line tension of the pore is negative
and the pore is stable in tensionless membranes. Another agent that in
uences the
line tension of the pore is oil (short hydrophobic chains). The oil has a con guration
space larger than the one of the lipids and partitions to relax the frustration of the
lipids at the interfaces and increases the line tension of the pore (the membrane is
more resistant under lateral tension).
The model parameters have a large in
uence on the equilibrium properties of a stalk
and we study the characteristic sizes of stalks depending on the hydration between two
opposed bilayers and compare the results to other simulation models and experimental
data. We show how hydration and lateral tension in
uence bilayer repulsion and how
the combined e ect of both contributions leads to membrane fusion. | de |
| dc.contributor.coReferee | Groot, Bert de Prof. Dr. | de |
| dc.subject.eng | Lipid membranes | de |
| dc.subject.eng | Molecular Dynamics | de |
| dc.subject.eng | Coarse-grained | de |
| dc.subject.eng | Monte Carlo | de |
| dc.subject.eng | Membrane fusion | de |
| dc.identifier.urn | urn:nbn:de:gbv:7-11858/00-1735-0000-000D-F28E-0-0 | de |
| dc.affiliation.institute | Fakultät für Physik | de |
| dc.identifier.ppn | 737346523 | de |