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Diffusion and Solid State NMR Studies of Structures in Model Biological Membranes

CHO, HYO SOON (2011) Diffusion and Solid State NMR Studies of Structures in Model Biological Membranes. Doctoral Dissertation, University of Pittsburgh.

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    Abstract

    We studied the structures in model biological membranes using solid state NMR and NMR diffusion microscopy. We have created a stable bicelle system containing cholesterol, unsaturated and saturated lipids, capable of forming micron-scale lipid domains and suitable for structural biology studies of membrane proteins. The domains were observed by measuring time-dependent diffusion constants reflecting restricted diffusion of the lipids within micron-scale regions of the bicelles. We observed the correlation of bilayer structure of diverse bicelle systems with their alignment capability, using 31P NMR to measure the density of perforations in the bilayer as a function of bicelle alignment. We found a critical density for optimal bicelle alignment, applicable to bicelles of different lipid compositions. We were able to measure the effect of the perforation density on micron-scale domain formation in lipid bilayers. The perforations redistributed line active lipids within the bilayer, affecting the bulk line tension of the lipid domain. This work demonstrated that membrane topology can control domain formation.


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    Item Type: University of Pittsburgh ETD
    Creators/Authors:
    CreatorsEmailORCID
    CHO, HYO SOONwish43043@gmail.com
    ETD Committee:
    ETD Committee TypeCommittee MemberEmailORCID
    Committee ChairSpence, Megan M.mmspence@gmail.com
    Committee MemberWaldeck, David
    Committee Membervan der Wel, Patrick
    Committee MemberSaxena, Sunil
    Title: Diffusion and Solid State NMR Studies of Structures in Model Biological Membranes
    Status: Unpublished
    Abstract: We studied the structures in model biological membranes using solid state NMR and NMR diffusion microscopy. We have created a stable bicelle system containing cholesterol, unsaturated and saturated lipids, capable of forming micron-scale lipid domains and suitable for structural biology studies of membrane proteins. The domains were observed by measuring time-dependent diffusion constants reflecting restricted diffusion of the lipids within micron-scale regions of the bicelles. We observed the correlation of bilayer structure of diverse bicelle systems with their alignment capability, using 31P NMR to measure the density of perforations in the bilayer as a function of bicelle alignment. We found a critical density for optimal bicelle alignment, applicable to bicelles of different lipid compositions. We were able to measure the effect of the perforation density on micron-scale domain formation in lipid bilayers. The perforations redistributed line active lipids within the bilayer, affecting the bulk line tension of the lipid domain. This work demonstrated that membrane topology can control domain formation.
    Date: 16 September 2011
    Date Type: Completion
    Defense Date: 23 June 2011
    Approval Date: 16 September 2011
    Submission Date: 28 June 2011
    Access Restriction: No restriction; The work is available for access worldwide immediately.
    Patent pending: No
    Institution: University of Pittsburgh
    Thesis Type: Doctoral Dissertation
    Refereed: Yes
    Degree: PhD - Doctor of Philosophy
    URN: etd-06282011-163133
    Uncontrolled Keywords: bicelle; diffusion
    Schools and Programs: Dietrich School of Arts and Sciences > Chemistry
    Date Deposited: 10 Nov 2011 14:48
    Last Modified: 19 Jun 2012 13:32
    Other ID: http://etd.library.pitt.edu/ETD/available/etd-06282011-163133/, etd-06282011-163133

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