TemperatureDependent Electron Paramagnetic Resona

Authors: D Yonar N Horasanb M Maral Sünnetçioğlu

Publish Date: 2016/07/20

Volume: 83, Issue: 3, Pages: 517-524

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Abstract

Free docosahexaenoic acid DHAn3 and gamma linolenic acid GLAn6 effects on dimyristoyl phosphatidylcholine DMPC membranes were studied as a function of temperature by electron paramagnetic resonance EPR spectroscopy 5 and 16doxyl stearic acid 5 16DS spin labels were utilized to obtain information from the interfacial and alkyl chain region respectively In the studied temperature range the presence of DHAn3 or GLAn6 caused decreases in maximum hyperfi ne splitting values and correlation times of DMPC membranes Both in the interfacial region and depths of membrane changes were more pronounced for DHAn3 in pure DMPC In the presence of cholesterol CH DHAn3 and GLAn6 effects were similar and more pronounced in the depths of the membrane The changes in the structure and dynamics of samples were obtained from simulations of spectra which indicated some changes in the number of spectral components by incorporation of DHAn3 and GLAn6 In the interfacial region and below the main phase transition temperature of DMPC there was an increase in heterogeneity For temperatures above the phase transition a more homogeneous environment for spin label was obtained in the presence of fatty acids

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