Investigating the Molecular Order and Orientation of Cholesterol in Mixtures of Polyunsaturated Phospholipids

The Atrium, University of Guelph Institutional Repository

Investigating the Molecular Order and Orientation of Cholesterol in Mixtures of Polyunsaturated Phospholipids

Show full item record

Title: Investigating the Molecular Order and Orientation of Cholesterol in Mixtures of Polyunsaturated Phospholipids
Author: Braithwaite, Iain M.
Department: Department of Physics
Program: Physics
Advisor: Davis, James H.
Abstract: Cholesterol is critical to ensure proper functioning of a membrane. Despite this, the movement of cholesterol within the cell is not fully understood. The molecular order of binary and ternary mixtures of polyunsaturated fatty acids with varying degrees of hy- drocarbon chain unsaturation with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and/or cholesterol was studied using 2H NMR. The introduction of cholesterol into sam- ples of 18:1PC, 18:2PC (unsaturated lipid/DMPC-d54/CHOL, 75:5:20mol%) increased the C-2H bond order by ∼30%. Similar bond ordering was found for 20:4PC and 22:6PC samples, however, they were temperature dependent. A two-phase region (lo-ld) was found for 22:6PC:DMPC-d54/CHOL (75:5:20mol%) for temperatures below 286.7 K. The reorientation axis formed an angle of 78±4◦ with respect to the C3-2H bond vector re- gardless of the lipid. The order parameter of cholesterol was temperature independent, and ranged from 0.69±0.04 to 0.78±0.04 depending on the lipid unsaturation. The re- orientation axis of cholesterol was oriented at ∼25◦ to the bilayer normal.
URI: http://hdl.handle.net/10214/2885
Date: 2011-08-26


Files in this item

Files Size Format View Description
Thesis.pdf 4.368Mb PDF View/Open MSc. Thesis for Iain Braithwaite

This item appears in the following Collection(s)

Show full item record

Search the Atrium


Advanced Search

Browse

My Account