Aggregation and Dynamics of Oligocholate Transporters in Phospholipid Bilayers Revealed by Solid-State NMR Spectroscopy
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The Department of Chemistry seeks to provide students with a foundation in the fundamentals and application of chemical theories and processes of the lab. Thus prepared they me pursue careers as teachers, industry supervisors, or research chemists in a variety of domains (governmental, academic, etc).
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The Department of Chemistry was founded in 1880.
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1880-present
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- College of Liberal Arts and Sciences (parent college)
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Abstract
Macrocycles made of cholate building blocks were previously found to transport glucose readily across lipid bilayers. In this study, an 15N, 13Cα-labeled glycine was inserted into a cyclic cholate trimer and attached at the end of a linear trimer, respectively. The isotopic labeling allowed us to use solid-state NMR spectroscopy to study the dynamics, aggregation, and depth of insertion of these compounds in lipid membranes. The cyclic compound was found to be mostly immobilized in DLPC, POPC/POPG, and POPC/POPG/cholesterol membranes, whereas the linear trimer displayed large-amplitude motion that depended on the membrane thickness and viscosity. 13C-detected 1H spin diffusion experiments revealed the depth of insertion of the compounds in the membranes, as well as their contact with water molecules. The data support a consistent stacking model for the cholate macrocycles in lipid membranes, driven by the hydrophobic interactions of the water molecules in the interior of the macrocycles. The study also shows a strong preference of the linear trimer for the membrane surface, consistent with its lack of transport activity in earlier liposome leakage assays.
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Reprinted (adapted) with permission from Langmuir 28 (2012): doi:10.1021/la303661p. Copyright 2012 American Chemical Society.