کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9587302 1393234 2005 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Backbone-only restraints for fast determination of the protein fold: The role of paramagnetism-based restraints. Cytochrome b562 as an example
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Backbone-only restraints for fast determination of the protein fold: The role of paramagnetism-based restraints. Cytochrome b562 as an example
چکیده انگلیسی
CHα residual dipolar couplings (Δrdc's) were measured for the oxidized cytochrome b562 from Escherichia coli as a result of its partial self-orientation in high magnetic fields due to the anisotropy of the overall magnetic susceptibility tensor. Both the low spin iron (III) heme and the four-helix bundle fold contribute to the magnetic anisotropy tensor. CHα Δrdc's, which span a larger range than the analogous NH values (already available in the literature) sample large space variations at variance with NH Δrdc's, which are largely isooriented within α helices. The whole structure is now significantly refined with the chemical shift index and CHα Δrdc's. The latter are particularly useful also in defining the molecular magnetic anisotropy parameters. It is shown here that the backbone folding can be conveniently and accurately determined using backbone restraints only, which include NOEs, hydrogen bonds, residual dipolar couplings, pseudocontact shifts, and chemical shift index. All these restraints are easily and quickly determined from the backbone assignment. The calculated backbone structure is comparable to that obtained by using also side chain restraint. Furthermore, the structure obtained with backbone only restraints is, in its whole, very similar to that obtained with the complete set of restraints. The paramagnetism based restraints are shown to be absolutely relevant, especially for Δrdc's.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Magnetic Resonance - Volume 172, Issue 2, February 2005, Pages 191-200
نویسندگان
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