کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1960059 1057950 2005 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Dielectric and Calorimetric Studies of Hydrated Purple Membrane
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Dielectric and Calorimetric Studies of Hydrated Purple Membrane
چکیده انگلیسی

Purple membranes (PM) from halobacteria were hydrated to ∼0.4 and ∼0.2 g H2O/g of PM and studied by dielectric spectroscopy and differential scanning calorimetry between 120 and 300 K. The dielectric process, attributed to a local (β) relaxation of the confined supercooled water, shows an Arrhenius temperature behavior at low temperatures. In the case of the most hydrated PM a small deviation from the Arrhenius behavior occurs at 190–200 K together with a pronounced endothermic process and an increased activation energy. The observed crossover is accompanied by a reduction of the interlayer spacing due to the partial loss of the intermembrane water. All these effects at ∼200 K are consistent with a scenario where the local relaxation process merges with a nonobservable α-relaxation of the interlayer water, giving rise to a more liquid-like behavior of the interfacial water. For the less hydrated sample the effects are less pronounced and shift to a slightly higher temperature.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: - Volume 89, Issue 5, November 2005, Pages 3120–3128
نویسندگان
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