Title Artificial phospholipids systems for investigations of protein and peptide interactions with biological membranes /
Translation of Title Dirbtinės fosfolipidinės sistemos baltymų bei peptidų sąveikos su biologinėmis membranomis tyrimams.
Authors Budvytytė, Rima
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Pages 50
Keywords [eng] membranes ; phospholipids ; impedance ; toxins ; amyloids
Abstract [eng] The main object of this thesis is tethered bilayer membranes (tBLM) on gold substrates, which are increasingly being used to mimic biomembranes in studies of protein reconstitution and function. We have developed a tBLM as stable model in which thiolated anchor lipids span a hydrated layer that separates the membrane from its solid support. The dynamic properties of phospholipids in tBLM were studied by fluorescence correlation spectroscopy comparing different amount of anchor molecules. Electrochemical parameters of these tBLM were studied with electrochemical impedance spectroscopy (EIS). To change the membrane composition, we suggest applying a method of direct lipid exchange between the vesicles and membranes. In this work EIS was used to determined electrical characteristics of tBLM and also was studied interaction of tBLM between pores forming toxins: α-hemolysin, antrax toxin and vaginolysin. There are iliustrated that the pores formed by the toxins significantly alter the membrane conductance. The activation energy of ion transport through the α-HL and PA63 pore barrier was determined. These results shows that both toxins form functionl water filled pores, in which the ions are travelling in an environment similar to the bulk of the solution. A central event in pathogenesis of Alzheimer’s disease is thought to be intracellular and extracellular accumulation of low molecular mass peptides - β-amyloids (Aβ1-42). In this work different sizes of soluble synthetic Aβ1-42 oligomers were used to determine their affinity to artificial phospholipid membranes. Membrane composition was found to be one of the important factors affecting binding of the Aβ oligomers to phospholipid vesicles. The link between the size of soluble Aβ1-42 oligomers and their neurotoxicity were observed.
Type Summaries of doctoral thesis
Language English
Publication date 2012