Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Molecular Dynamics Simulations of Membrane-Sugar Interactions
Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
Stockholm University, Faculty of Science, Department of Organic Chemistry.
Show others and affiliations
2013 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 117, no 22, 6667-6673 p.Article in journal (Refereed) Published
Abstract [en]

It is well documented that disaccharides in general and trehalose (TRH) in particular strongly affect physical properties and functionality of lipid bilayers. We investigate interactions between lipid membranes formed by 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and TRH by means of molecular dynamics (MD) computer simulations. Ten different TRH concentrations were studied in the range W-TRH = 0-0.20 (w/w). The potential of mean force (PMF) for DMPC bilayer TRH interactions was determined using two different force fields, and was subsequently used in a simple analytical model for description of sugar binding at the membrane interface. The MD results were in good agreement with the predictions of the model. The net affinities of TRH for the DMPC bilayer derived from the model and MD simulations were compared with experimental results. The area per lipid increases and the membrane becomes thinner with increased TRH concentration, which is interpreted as an intercalation effect of the TRH molecules into the polar part of the lipids, resulting in conformational changes in the chains. These results are consistent with recent experimental observations. The compressibility modulus related to the fluctuations of the membrane increases dramatically with increased TRH concentration, which indicates higher order and rigidity of the bilayer. This is also reflected in a decrease (by a factor of 15) of the lateral diffusion of the lipids. We interpret these observations as a formation of a glassy state at the interface of the membrane, which has been suggested in the literature as a hypothesis for the membrane sugar interactions.

Place, publisher, year, edition, pages
2013. Vol. 117, no 22, 6667-6673 p.
National Category
Physical Chemistry
Research subject
Physical Chemistry
Identifiers
URN: urn:nbn:se:su:diva-92443DOI: 10.1021/jp402385dISI: 000320215200009OAI: oai:DiVA.org:su-92443DiVA: diva2:639027
Funder
Swedish Research Council
Note

AuthorCount:6;

Available from: 2013-08-05 Created: 2013-08-05 Last updated: 2017-12-06Bibliographically approved
In thesis
1. Computer Simulations of Membrane–Sugar Interactions
Open this publication in new window or tab >>Computer Simulations of Membrane–Sugar Interactions
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Carbohydrate molecules are essential parts of living cells. They are used as energy storage and signal substances, and they can be found incorporated in the cell membranes as attachments to glycoproteins and glycolipids, but also as free molecules. In this thesis the effect of carbohydrate molecules on phospholipid model membranes have been investigated by the means of Molecular Dynamics (MD) computer simulations.

The most abundant glycolipid in nature is the non-bilayer forming monogalactosyldiacylglycerol (MGDG). It is known to be important for the membrane stacking typical for the thylakoid membranes in plants, and has also been found essential for processes related to photosynthesis. In Paper I, MD simulations were used to characterize structural and dynamical changes in a lipid bilayer when MGDG is present. The simulations were validated by direct comparisons between dipolar couplings calculated from the MD trajectories, and those determined from NMR experiments on similar systems. We could show that most structural changes of the bilayer were a consequence of lipid packing and the molecular shape of MGDG.

In certain plants and organisms, the enrichment of small sugars such as sucrose and trehalose close to the membrane interfaces, are known to be one of the strategies to survive freezing and dehydration. The cryoprotecting abilities of these sugar molecules are long known, but the mechanisms at the molecular level are still debated. In Papers II–IV, the interactions of trehalose with a lipid bilayer were investigated. Calculations of structural and dynamical properties, together with free energy calculations, were used to characterize the effect of trehalose on bilayer properties. We could show that the binding of trehalose to the lipid bilayer follows a simple two state binding model, in agreement with recent experimental investigations, and confirm some of the proposed hypotheses for membrane–sugar interactions. The simulations were validated by dipolar couplings from our NMR investigations of TRH in a dilute liquid crystal (bicelles). Furthermore, the assumption about molecular structure being equal in the ordered and isotropic phases was tested and verified. This assumption is central for the interpretation of experimentally determined dipolar couplings in weakly ordered systems.

In addition, a coarse grain model was used to tackle some of the problems with slow dynamics that were encountered for trehalose in interaction with the bilayer. It was found that further developments of the interaction models are needed to properly describe the membrane–sugar interactions. Lastly, from investigations of trehalose curvature sensing, we concluded that it preferably interacts in bilayer regions with high negative curvature.

Place, publisher, year, edition, pages
Stockholm: Department of Materials and Environmental Chemistry (MMK), Stockholm University, 2016. 78 p.
Keyword
Molecular simulations, Molecular dynamics, Lipid bilayers, Carbohydrates, Biological membranes, Trehalose, Glycolipids, Membrane—sugar interactions
National Category
Physical Chemistry
Research subject
Physical Chemistry
Identifiers
urn:nbn:se:su:diva-127402 (URN)978-91-7649-363-2 (ISBN)
Public defence
2016-04-29, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.

Available from: 2016-04-06 Created: 2016-03-03 Last updated: 2017-02-20Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Kapla, JonStevensson, BaltzarEngström, OlofWidmalm, GöranMaliniak, Arnold
By organisation
Department of Materials and Environmental Chemistry (MMK)Department of Organic Chemistry
In the same journal
Journal of Physical Chemistry B
Physical Chemistry

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 48 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf