کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5377283 | 1389384 | 2006 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Nonequilibrium protein folding dynamics: laser-induced pH-jump studies of the helix-coil transition
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
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چکیده انگلیسی
The kinetics of the helix-coil transition of poly-l-glutamate were measured in the range of 40Â ns to 10Â s using a laser-induced pH-jump coupled with time-resolved infrared spectroscopy. Folding of the polypeptide in D2O was initiated by photolyzing o-nitrobenzaldehyde, which releases a deuteron, creating a rapid decrease in pD. Side-chain deuteration and conformational changes were monitored independently by varying the IR probe wavelength. The kinetics of the peptide conformational changes observed in the amide I region depended on the initial fraction of helical residues. With essentially no initial helix, amide I absorption changes were indistinguishable from those of instrument response, leading to the conclusion that helix initiation occurs in less than 40Â ns. When the initial helix fraction is 0.13, the folding lifetime is lengthened to 625Â ns, as predicted by helix-coil theory. We also observe evidence for a kinetically-trapped, nonproductive intermediate formed as the result of rapid deuteration of the unfolded state.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Physics - Volume 323, Issue 1, 31 March 2006, Pages 2-10
Journal: Chemical Physics - Volume 323, Issue 1, 31 March 2006, Pages 2-10
نویسندگان
Timothy P. Causgrove, R. Brian Dyer,