A DFT study of infrared spectrum of sphingomyelin lipid molecule with calcium cation

Authors

  • K. Sugimori,

    Corresponding author
    1. Department of Social Work, Faculty of Social Science, Kinjo University, 1200 Kasama, Hakusan 924-8511, Japan
    • Department of Social Work, Faculty of Social Science, Kinjo University, 1200 Kasama, Hakusan 924-8511, Japan
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  • H. Kawabe,

    1. Department of Social Work, Faculty of Social Science, Kinjo University, 1200 Kasama, Hakusan 924-8511, Japan
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  • H. Nagao,

    1. Division of Mathematical and Physical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
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  • K. Nishikawa

    1. Division of Mathematical and Physical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
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Abstract

One of the phospholipids, sphingomyelin (SM) is the most abundant component of mammalian membranes in brain and nervous tissues. It plays an important role for apoptosis, aging, and signal transduction with cations. Recently, Yappert and co-workers have shown that human lens sphingomyelin and its hydrogenated derivative, dihydrosphingomyelin (DHSM) are interacted with Ca2+ ions to develop human cataracts. In this study, we investigate conformational differences between an isolated SM/DHSM molecule and Ca2+-coordinated form by using density functional theory (DFT) calculations. B3LYP functional and 6-31G(d,p) double-ζ split-valence basis set is used for geometry optimization and normal mode analysis. One of resultant conformers of SMs has hydrogen bonding between hydroxyl and phosphate group, whereas another conformer has hydrogen bonding between hydroxyl and amide group. The red shift of calculated vibrational frequencies of amide band due to Ca2+ is compared with experimental infrared spectrum. Finally, we discuss the Ca2+-induced effects from conformational and spectroscopic point of view to compare the experimental results. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008

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