Ribosome-associated factor Y adopts a fold resembling a double-stranded RNA binding domain scaffold.
Ribosome-associated factor Y adopts a fold resembling a double-stranded RNA binding domain scaffold.
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核糖体相关因子 Y 采用类似于双链 RNA 结合结构域支架的折叠。
DOI：
10.1046/j.1432-1033.2002.03222.x
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
Patel,DinshawJ
中科院分区：
文献类型：
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作者：
Ye,Keqiong;Serganov,Alexander;Hu,Weidong;Garber,Maria;Patel,DinshawJ
大肠杆菌大肠杆菌蛋白Y(Py)与核糖体小亚基结合，在细菌经历环境压力时稳定核糖体不解离。PY在体外抑制 的翻译，很可能是通过干扰氨基酰tRNA与核糖体A位点的结合而实现的。这种翻译停滞可能会调节细胞对环境条件的整体适应。我们测定了一个112个残基的Py的三维溶液结构，并用核磁共振波谱研究了它的主链动力学。该结构具有βαβββα拓扑结构，表示由两个几乎平行的α螺旋组成的紧凑的双层三明治，紧靠在四链β片材的同一侧。蛋白质的23个C末端残基是无序的。由残留偶极耦合数据提供的长程角度限制被证明是精确确定螺旋1位置的关键。我们的数据证实了螺旋1的C-末端区域和连接该螺旋与链β2的环在ms-µS时间尺度上显示出显著的构象交换，这可能与Py与核糖体亚基的相互作用有关。蛋白质表面保守残基的分布突出了朝向两个α螺旋的C-末端片段的正电荷区域，这很可能构成了一个RNA结合部位。尽管序列相似性有限，但观察到的Py的βαβββα拓扑类似于双链αβββα结合域的拓扑。这可能是因为Py中假定的RNA结合部位与dsRBD的RNA结合表面不一致，所以Py的功能性质可能与dsRBD的功能性质不同。
Escherichia coliprotein Y (pY) binds to the small ribosomal subunit and stabilizes ribosomes against dissociation when bacteria experience environmental stress. pY inhibits translationin vitro, most probably by interfering with the binding of the aminoacyl‐tRNA to the ribosomal A site. Such a translational arrest may mediate overall adaptation of cells to environmental conditions. We have determined the 3D solution structure of a 112‐residue pY and have studied its backbone dynamic by NMR spectroscopy. The structure has a βαβββα topology and represents a compact two‐layered sandwich of two nearly parallel α helices packed against the same side of a four‐stranded β sheet. The 23 C‐terminal residues of the protein are disordered. Long‐range angular constraints provided by residual dipolar coupling data proved critical for precisely defining the position of helix 1. Our data establish that the C‐terminal region of helix 1 and the loop linking this helix with strand β2 show significant conformational exchange in the ms–µs time scale, which may have relevance to the interaction of pY with ribosomal subunits. Distribution of the conserved residues on the protein surface highlights a positively charged region towards the C‐terminal segments of both α helices, which most probably constitutes an RNA binding site. The observed βαβββα topology of pY resembles the αβββα topology of double‐stranded RNA‐binding domains, despite limited sequence similarity. It appears probable that functional properties of pY are not identical to those of dsRBDs, as the postulated RNA‐binding site in pY does not coincide with the RNA‐binding surface of the dsRBDs.