Institute of Biochemistry, Cluster of Excellence Frankfurt-Macromolecular Complexes, Biocenter, Goethe University, Max-von-Laue Strasse 9, D-60438 Frankfurt/Main, Germany.
Proc Natl Acad Sci U S A. 2011 Feb 22;108(8):3228-33. doi: 10.1073/pnas.1015953108. Epub 2011 Feb 3.
Despite some appealing similarities of protein synthesis across all phyla of life, the final phase of mRNA translation has yet to be captured. Here, we reveal the ancestral role and mechanistic principles of the newly identified twin-ATPase ABCE1 in ribosome recycling. We demonstrate that the unique iron-sulfur cluster domain and an ATP-dependent conformational switch of ABCE1 are essential both for ribosome binding and recycling. By direct (11) interaction, the peptide release factor aRF1 is shown to synergistically promote ABCE1 function in posttermination ribosome recycling. Upon ATP binding, ABCE1 undergoes a conformational switch from an open to a closed ATP-occluded state, which drives ribosome dissociation as well as the disengagement of aRF1. ATP hydrolysis is not required for a single round of ribosome splitting but for ABCE1 release from the 30S subunit to reenter a new cycle. These results provide a mechanistic understanding of final phases in mRNA translation.
尽管生命所有门都有一些吸引人的蛋白质合成相似之处，但 mRNA 翻译的最后阶段尚未被捕获。在这里，我们揭示了新鉴定的双 ATP 酶 ABCE1 在核糖体回收中的古老作用和机械原理。我们证明，独特的铁硫簇结构域和 ABCE1 的 ATP 依赖性构象开关对于核糖体结合和回收都是必不可少的。通过直接（11）相互作用，肽释放因子 aRF1 被证明协同促进终止后核糖体回收中 ABCE1 的功能。当结合 ATP 时，ABCE1 经历从开放到封闭 ATP 封闭状态的构象转变，这促使核糖体解离以及 aRF1 的脱离。ATP 水解不是一轮核糖体分裂所必需的，但对于 ABCE1 从 30S 亚基释放以重新进入新循环是必需的。这些结果提供了对 mRNA 翻译最后阶段的机制理解。
