| Lipid Membranes with a Majority of Cholesterol: Applications to the Ocular Lens and Aquaporin 0. | |
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MedLine Citation:
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PMID: 21539340 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Using molecular dynamics (MD) simulations, we studied the structure and dynamics of two dimyristoylphosphatidylcholine (DMPC):cholesterol bilayers at concentrations representative of the ocular lens (ratios of 1:1 and 1:2). These MD simulations agree well with experimental deuterium order parameters and bilayer peak-to-peak distances. Although it is known that the average surface area per lipid rapidly decreases from low to moderate levels of cholesterol, our simulations indicate that there is a relatively small change in the average lipid area from 50 to 66.7% cholesterol (40.5 ± 0.2 and 39.5 ± 0.1 Å(2)/lipid, respectively). Radial distribution functions for the hydroxyl group on cholesterol indicate the formation of cholesterol-only nanoscale domains for the membrane with 66.7% cholesterol but a uniform distribution of cholesterol and DMPC for the membrane with 50% cholesterol. These small domains form a single shell of hexagonally packed cholesterols that are interconnected in a web-like structure of cholesterol. Calculations of internal DMPC dynamics show that the relaxation times for carbon-hydrogen reorientation of choline decrease with an increase in cholesterol, but the main body (carbonyl-glycerol to C11) is independent of cholesterol concentration. MD simulations of the aquaporin 0 tetramer show stabilization in its interactions with lipid membranes containing cholesterol by forming ring-ring stacking between surface aromatic residues of the protein and the rings of cholesterol. Moreover, there is an increase in hydrogen bonds with longer lifetimes in a mixed bilayer of DMPC and cholesterol. |
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Authors:
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Joseph W O'Connor; Jeffery B Klauda |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-5-3 |
Journal Detail:
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Title: The journal of physical chemistry. B Volume: - ISSN: 1520-5207 ISO Abbreviation: - Publication Date: 2011 May |
Date Detail:
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Created Date: 2011-5-4 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101157530 Medline TA: J Phys Chem B Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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Department of Chemical and Biomolecular Engineering, University of Maryland , College Park, Maryland 20742, United States. |
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Descriptor/Qualifier:
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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