کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5914997 | 1162770 | 2010 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Measuring the conformational space of square four-helical bundles with the program samCC
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
زیست شناسی مولکولی
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چکیده انگلیسی
Four-helical bundles are the most abundant topological motif among helical folds. Their constituent helices show crossing angles that mainly cluster around +20° (aligned) or â50° (orthogonal). Bundles with all helices aligned are called 'square' and comprise four-helical coiled coils as their structurally most regular form. Since coiled coils can be described fully by parametric equations, they can serve as a reference point for quantifying the conformational space of all square bundles. To this end we have developed a program, samCC, which measures the deviation of a given bundle from an idealized coiled coil and decomposes this into axial rotation and axial, radial, and angular shifts. We present examples of analyses performed with the program and focus in particular on the axial rotation states of helices in coiled coils, in order to gain further insight into a proposed mechanism for transmembrane signal transduction, which involves a 26° axial rotation of helices between a canonical coiled coil and a variant called the Alacoil. We find that, unlike expected from the mechanistic model, coiled coils show a continuum of axial rotation states, suggesting that the Alacoil does not represent a single, defined state. We also find that one of the originally proposed Alacoil proteins, Rop, in fact has canonical packing. SamCC is freely available as a web service at http://toolkit.tuebingen.mpg.de/samcc.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Structural Biology - Volume 170, Issue 2, May 2010, Pages 226-235
Journal: Journal of Structural Biology - Volume 170, Issue 2, May 2010, Pages 226-235
نویسندگان
Stanislaw Dunin-Horkawicz, Andrei N. Lupas,