کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10537691 | 962814 | 2005 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Metal binding of metallothionein-3 versus metallothionein-2: lower affinity and higher plasticity
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کلمات کلیدی
ESI-MSDTTTFEESI MSMT-3Alzheimer's disease - بیماری آلزایمرdithiothreitol - دیتیوتریتولcircular dichroism - رنگ تابی دورانیelectrospray ionization mass spectroscopy - طیف سنجی جرم یونیزاسیون الکترو اسپریCD spectroscopy - طیف سنجی سی دیMetallothionein - متالوتونیئینSecondary structure prediction - پیش بینی ساختار ثانویه
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله

چکیده انگلیسی
Mammalian metallothioneins (MTs) are involved in cellular metabolism of zinc and copper and in cytoprotection against toxic metals and reactive oxygen species. MT-3 plays a specific role in the brain and is down-regulated in Alzheimer's disease. To evaluate differences in metal binding, we conducted direct metal competition experiments with MT-3 and MT-2 using electrospray ionization mass spectroscopy (ESI-MS). Results demonstrate that MT-3 binds Zn2+ and Cd2+ ions more weakly than MT-2 but exposes higher metal-binding capacity and plasticity. Titration with Cd2+ ions demonstrates that metal-binding affinities of individual clusters of MT-2 and MT-3 are decreasing in the following order: four-metal cluster of MT-2>three-metal cluster of MT-2âfour-metal cluster of MT-3>three-metal cluster of MT-3>extra metal-binding sites of MT-3. To evaluate the reasons for weaker metal-binding affinity of MT-3 and the enhanced resistance of MT-3 towards proteolysis under zinc-depleted cellular conditions, we studied the secondary structures of apo-MT-3 and apo-MT-2 by CD spectroscopy. Results showed that apo-MT-3 and apo-MT-2 have almost equal helical content (approximately 10%) in aqueous buffer, but that MT-3 had slightly higher tendency to form α-helical secondary structure in TFE-water mixtures. Secondary structure predictions also indicated some differences between MT-3 and MT-2, by predicting random coil for common MTs, but 22% α-helical structure for MT-3. Combined, all results highlight further differences between MT-3 and common MTs, which may be related with their functional specificities.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics - Volume 1747, Issue 2, 14 March 2005, Pages 205-211
Journal: Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics - Volume 1747, Issue 2, 14 March 2005, Pages 205-211
نویسندگان
Peep Palumaa, Indrek Tammiste, Keiu Kruusel, Liina Kangur, Hans Jörnvall, Rannar Sillard,