Effect of membrane thickness and unsaturation on dye efflux rates induced by [delta]-Lysin from phosphatidylcholine vesicles
- UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
- Diana Wu (Creator)
- Institution
- The University of North Carolina Wilmington (UNCW )
- Web Site: http://library.uncw.edu/
- Advisor
- Paulo Almeida
Abstract: An important region of the cellular membrane that appears to have major influence on
membrane-peptide interactions is the hydrophobic acyl chain region. In this study two lipid
series were used to determine whether specificity towards membranes is influenced by acyl chain
length, or membrane thickness, or by the degree of acyl chain unsaturation. Additionally, this
quantitative investigation also provided insight on the effects of free volume and bilayer
elasticity. The interaction of the peptide d-lysin, a 26-residue peptide, to lipid bilayers was
studied using stopped-flow fluorescence. Samples of carboxyfluorescein filled vesicles of
various lipid concentrations were mixed with d-lysin resulting in dye efflux. The experimental
curves of carboxyfluorescein efflux as a function of time were measured at lipid concentrations
ranging from 12.5 µM to 200 µM.
Constant t values were calculated to determine the weighted average of the relaxation
times of each carboxyfluorescein release function. It was found the main cause for dye efflux
was a thinner membrane. Also, bending of the membrane was found to be dependent on the
thickness of the bilayer. The stretching ability of the membrane had less significance in peptide
insertion. As a result of bending stiffness being a major factor for peptide insertion, it appears
that d-lysin binds to the surface of the membrane due to the hydrophobic effect, and sink as a
‘wedge’ into the lipid bilayer.
Effect of membrane thickness and unsaturation on dye efflux rates induced by [delta]-Lysin from phosphatidylcholine vesicles
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Created on 1/1/2009
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Additional Information
- Publication
- Thesis
- A Thesis Submitted to the University of North Carolina Wilmington in Partial Fulfillment Of the Requirements for the Degree of Master of Science
- Language: English
- Date: 2009
- Keywords
- Cell membranes, Flow cytometry, Lipids--Research, Membrane lipids, Membranes (Biology)--Fluidity, Membranes (Biology)--Permeability, Membranes (Biology)--Physiology
- Subjects
- Membranes (Biology) -- Fluidity
- Membranes (Biology) -- Physiology
- Lipids -- Research
- Flow cytometry
- Cell membranes
- Membranes (Biology) -- Permeability
- Membrane lipids