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Tesi etd-09112019-182738


Tipo di tesi
Tesi di laurea magistrale
Autore
SAGRESTI, LUCA
URN
etd-09112019-182738
Titolo
Structure and dynamics of a dye-labeled lipid in a model membrane bilayer: a computational study
Dipartimento
INGEGNERIA CIVILE E INDUSTRIALE
Corso di studi
MATERIALS AND NANOTECHNOLOGY
Relatori
relatore Brancato, Giuseppe
Parole chiave
  • DOPC
  • Lipid lateral diffusion
  • Molecular dynamics simulations
  • Rhodamine B-labeled lipids
  • Temperature dependence
Data inizio appello
04/10/2019
Consultabilità
Non consultabile
Data di rilascio
04/10/2089
Riassunto
Fluorescent probes are widely employed to label lipids for the investigation of structural and dynamic properties of model and cell membranes through optical microscopy techniques. Although the effect of tagging a lipid with an organic dye is generally assumed to be negligible, optically modified lipids can nonetheless affect the local lipid structure and, in turn, the lipid lateral mobility. In order to further investigate this potential issue, all-atom molecular dynamics (MD) simulations have been performed to study structural and dynamic effects in a model DOPC membrane in the presence of a standard Rhodamine
B-labeled DOPE lipid (RHB) as a function of temperature, i.e., 293 K, 303 K, and 320 K. As the temperature is increased, we observe similar changes in the structural properties of both pure DOPC and RHB-DOPC lipid bilayers: an increase of the area per lipid, a reduction of the membrane thickness and a decrease of lipid order parameters. The partial density profile of the RHB headgroups and their orientation within the lipid bilayer confirm the amphiphilic nature of the RHB fluorescent moiety, which mainly partitions in the DOPC glycerol backbone region at each temperature. Moreover, at all temperatures, the results on lipid lateral diffusion support a non-neutral role of the dye with respect to the unlabeled lipid mobility, thus
suggesting important implications for optical microscopy studies of lipid membranes.
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