کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1388524 982798 2008 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Site-specific interactions of copper(II) ions with heparin revealed with complementary (SRCD, NMR, FTIR and EPR) spectroscopic techniques
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Site-specific interactions of copper(II) ions with heparin revealed with complementary (SRCD, NMR, FTIR and EPR) spectroscopic techniques
چکیده انگلیسی

The interactions between Cu(II) ions and heparin were investigated using several complementary spectroscopic techniques. NMR indicated an initial binding phase involving specific coordination to four points in the structure that recur in slightly different environments throughout the heparin chain; the carboxylic acid group and the ring oxygen of iduronate-2-O-sulfate, the glycosidic oxygen between this residue and the adjacent (towards the reducing end) glucosamine and the 6-O-sulfate group. In contrast, the later binding phase showed little structural specificity. One- and two-dimensional correlated FTIR revealed that complex out of phase (asynchronous) conformational changes also occurred during the titration of Cu(II) ions into heparin, involving the CO and N–H stretches. EPR demonstrated that the environments of the Cu(II) ions in the initial binding phase were tetragonal (with slightly varied geometry), while the later non-specific phases exhibited conventional coordination. Visible spectroscopy confirmed a shift of the absorbance maximum. Titration of Cu(II) ions into a solution of heparin indicated (both by analysis of FTIR and EPR spectra) that the initial binding phase was complete by 15–20 Cu(II) ions per chain; thereafter the ions bound in the non-specific mode. Hetero-correlation spectroscopy (FTIR–CD) improved resolution and assisted assignment of the broad CD features from the FTIR spectra and indicated both in-phase and more complex out of phase (synchronous and asynchronous, respectively) changes in interactions within the heparin molecule during the titration of Cu(II) ions.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Carbohydrate Research - Volume 343, Issue 12, 11 August 2008, Pages 2184–2193
نویسندگان
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