Another piece of the ribosome:: solution structure of S16 and its location in the 30S subunit
Another piece of the ribosome:: solution structure of S16 and its location in the 30S subunit
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DOI：
10.1016/s0969-2126(00)00177-5
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发表时间：
2000-08-15
期刊：
影响因子：
--
通讯作者：
Härd, T
中科院分区：
文献类型：
--
作者：
Allard, P;Rak, AV;Härd, T
背景：X射线结晶学最近获得了细菌核糖体及其两个亚基的电子密度图，许多细菌核糖体亚基的结构细节正在得到解决。补充结构和阐明rRNA和蛋白质堆积细节的一种方法是确定单个蛋白质组分的结构，并将这些结构模拟到现有的中分辨电子密度中。结果：我们已经确定了来自Thermus thermophilus的核糖体蛋白S16的溶液结构。S16是一种混合碱性磷酸酶蛋白，具有一种新型的折叠支架，该折叠支架基于一个五链的反平行/平行的β片断，三个部分无序的大环从片层延伸出来，两个ct螺旋堆积在其凹面上。表面静电势的计算表明，表面静电势有较大的连续正电势区和较小的负电势区。结论：S16在由螺旋21和其他几个未分配的rRNA螺旋形成的狭窄缝隙中的位置和方向与S16形状对应的电子密度、羟基自由基保护数据和S16的静电表面电位一致。与S16相邻的两个蛋白质是S4和S20，它们促进了S16与30S亚基的结合。总体而言，这项工作说明了将单个组分的高分辨率核磁共振(核磁共振)结构与低分辨率X射线图相结合来阐明大型络合物的结构的好处。
Background: X-ray crystallography has recently yielded much-improved electron-density maps of the bacterial ribosome and its two subunits and many structural details of bacterial ribosome subunits are now being resolved. One approach to complement the structures and elucidate the details of rRNA and protein packing is to determine structures of individual protein components and model these into existing intermediate resolution electron density.Results: We have determined the solution structure of the ribosomal protein S16 from Thermus thermophilus. S16 is a mixed alp protein with a novel folding scaffold based on a five-stranded antiparallel/parallel beta sheet, Three large loops, which are partially disordered, extend from the sheet and two ct helices are packed against its concave surface. Calculations of surface electrostatic potentials show a large continuous area of positive electrostatic potential and smaller areas of negative potential. S16 was modeled into a 5.5 Angstrom electron-density map of the T. thermophilus 30S ribosomal subunit.Conclusions: The location and orientation of S16 in a narrow crevice formed by helix 21 and several other unassigned rRNA helices is consistent with electron density corresponding to the shape of S16, hydroxyl radical protection data, and the electrostatic surface potential of S16. Two protein neighbors to S16 are S4 and S20, which facilitate binding of S16 to the 30S subunit. Overall, this work exemplifies the benefits of combining high-resolution nuclear magnetic resonance (NMR) structures of individual components with low-resolution X-ray maps to elucidate structures of large complexes.