Sato Akiko, Watanabe Takumi, Maki Yasushi, Ueta Masami, Yoshida Hideji, Ito Yutaka, Wada Akira, Mishima Masaki
Graduate School of Science and Technology, Tokyo Metropolitan University, 1-1 Minamiosawa, Hachioji, Japan.
Biochem Biophys Res Commun. 2009 Nov 27;389(4):580-5. doi: 10.1016/j.bbrc.2009.09.022. Epub 2009 Sep 10.
The 70S Escherichia coli ribosome dimerizes to form an inactive 100S ribosome during stationary phase, which is called "ribosome hibernation". The hibernation promoting factor HPF plays a crucial role in 100S ribosome formation. However, YfiA, a known paralog of HPF inhibits 100S formation, although it shares high sequence similarity. Here, we report the first solution structure of HPF as determined by multi-dimensional NMR. HPF adopts betaalphabetabetabetaalpha-fold and the overall structure is similar to YfiA as expected. However, detailed structure comparison based on the determined structure in this study revealed that there are remarkable differences around the C-terminal portion of helix alpha2, which is not predicted by homology modeling. Furthermore, some acidic residues conserved only in HPF are located at the rim of the common basic patch.
在稳定期，70S大肠杆菌核糖体二聚化形成无活性的100S核糖体，这一过程被称为“核糖体休眠”。休眠促进因子HPF在100S核糖体形成中起关键作用。然而，YfiA是HPF的一个已知旁系同源物，尽管它与HPF具有高度的序列相似性，但却抑制100S核糖体的形成。在此，我们报道了通过多维核磁共振确定的HPF的首个溶液结构。HPF采用β-α-α-β-α折叠，整体结构如预期的那样与YfiA相似。然而，基于本研究确定的结构进行的详细结构比较表明，在α2螺旋的C端部分周围存在显著差异，这是同源建模无法预测的。此外，一些仅在HPF中保守的酸性残基位于共同碱性区域的边缘。
