A comparative study of the membrane-active beta-sheet peptide protegrin with the alpha-helical peptide alamethicin

dc.contributor.advisorHuang, Huey W.
dc.creatorHeller, William Thomas
dc.date.accessioned2009-06-04T08:44:07Z
dc.date.available2009-06-04T08:44:07Z
dc.date.issued1999
dc.description.abstractThe interactions of the membrane-active peptides alamethicin and protegrin with lipid bilayers are studied. The influence of the bilayer composition on the orientation transition of alamethicin is studied using oriented circular dichroism. The makeup of the headgroup region of the bilayer is altered while the composition of the hydrocarbon chains remains constant. When a smaller lipid headgroup is added to the bilayer, the insertion transition shifts to higher peptide concentrations. This can be explained as a reduction of the energy cost of adsorbing the peptide in the bilayer due to the smaller lipid headgroup. The interactions of the beta-sheet peptide protegrin with model membranes are studied by oriented circular dichroism and lamellar x-ray diffraction. A transition between two states with distinct oriented circular dichroism spectra is observed which is a function of the peptide concentration and hydration. Lamellar x-ray diffraction indicates that protegrin produces membrane thinning in the same lipid system for peptide concentrations below those needed to bring on the transition. This leads to the conclusion that the low concentration and hydration state has protegrin adsorbed into the headgroup region of the bilayer parallel to the membrane surface. Comparisons between the behaviors of alamethicin and protegrins are drawn which suggests that the two peptides have the same mode of action.
dc.format.extent153 p.en_US
dc.format.mimetypeapplication/pdf
dc.identifier.callnoTHESIS PHYS. 1999 HELLER
dc.identifier.citationHeller, William Thomas. "A comparative study of the membrane-active beta-sheet peptide protegrin with the alpha-helical peptide alamethicin." (1999) Diss., Rice University. <a href="https://hdl.handle.net/1911/19391">https://hdl.handle.net/1911/19391</a>.
dc.identifier.urihttps://hdl.handle.net/1911/19391
dc.language.isoeng
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.
dc.subjectBiochemistry
dc.subjectBiophysics
dc.titleA comparative study of the membrane-active beta-sheet peptide protegrin with the alpha-helical peptide alamethicin
dc.typeThesis
dc.type.materialText
thesis.degree.departmentPhysics
thesis.degree.disciplineNatural Sciences
thesis.degree.grantorRice University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy
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