Graduate School of Life Science, University of Hyogo, Ako 678-1297, Japan.
FEBS Lett. 2012 Oct 19;586(20):3705-9. doi: 10.1016/j.febslet.2012.08.029. Epub 2012 Sep 6.
The bacterial translational GTPases release factor RF3 promotes translation termination by recycling RF1 or RF2. Here, we present the crystal structures of RF3 complexed with GDP and guanosine 3',5'-(bis)diphosphate (ppGpp) at resolutions of 1.8 and 3.0Å, respectively. ppGpp is involved in the so-called "stringent response" of bacteria. ppGpp binds at the same site as GDP, suggesting that GDP and ppGpp are two alternative physiologically relevant ligands of RF3. We also found that ppGpp decelerates the recycling of RF1 by RF3. These lines of evidence suggest that RF3 functions both as a cellular metabolic sensor and as a regulator.
细菌翻译中的 GTP 酶释放因子 RF3 通过循环利用 RF1 或 RF2 来促进翻译终止。在这里，我们呈现了 RF3 分别与 GDP 和鸟苷 3'，5'-(双)二磷酸（ppGpp）复合物的晶体结构，分辨率分别为 1.8 和 3.0Å。ppGpp 参与了细菌所谓的“严谨反应”。ppGpp 结合在与 GDP 相同的位点上，表明 GDP 和 ppGpp 是 RF3 的两种替代的生理相关配体。我们还发现 ppGpp 会使 RF3 对 RF1 的循环回收减速。这些证据表明 RF3 既作为细胞代谢传感器，又作为调节剂发挥作用。
