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包含eRF1 - eRF3或eRF1 - ABCE1的真核生物翻译终止复合物的冷冻电子显微镜结构

Cryoelectron microscopic structures of eukaryotic translation termination complexes containing eRF1-eRF3 or eRF1-ABCE1.

作者信息

Preis Anne, Heuer Andre, Barrio-Garcia Clara, Hauser Andreas, Eyler Daniel E, Berninghausen Otto, Green Rachel, Becker Thomas, Beckmann Roland

机构信息

Gene Center Munich, Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, 81377 Munich, Germany; Center for Integrated Protein Science Munich, Department of Biochemistry, Feodor-Lynen-Strasse 25, University of Munich, 81377 Munich, Germany.

Howard Hughes Medical Institute, Chevy Chase, MD 20815-6789, USA; Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.

出版信息

Cell Rep. 2014 Jul 10;8(1):59-65. doi: 10.1016/j.celrep.2014.04.058. Epub 2014 Jul 4.

Abstract

Termination and ribosome recycling are essential processes in translation. In eukaryotes, a stop codon in the ribosomal A site is decoded by a ternary complex consisting of release factors eRF1 and guanosine triphosphate (GTP)-bound eRF3. After GTP hydrolysis, eRF3 dissociates, and ABCE1 can bind to eRF1-loaded ribosomes to stimulate peptide release and ribosomal subunit dissociation. Here, we present cryoelectron microscopic (cryo-EM) structures of a pretermination complex containing eRF1-eRF3 and a termination/prerecycling complex containing eRF1-ABCE1. eRF1 undergoes drastic conformational changes: its central domain harboring the catalytically important GGQ loop is either packed against eRF3 or swung toward the peptidyl transferase center when bound to ABCE1. Additionally, in complex with eRF3, the N-terminal domain of eRF1 positions the conserved NIKS motif proximal to the stop codon, supporting its suggested role in decoding, yet it appears to be delocalized in the presence of ABCE1. These results suggest that stop codon decoding and peptide release can be uncoupled during termination.

摘要

终止和核糖体循环是翻译过程中的重要环节。在真核生物中,核糖体A位点的终止密码子由包含释放因子eRF1和结合鸟苷三磷酸(GTP)的eRF3的三元复合物解码。GTP水解后,eRF3解离,ABCE1可与负载eRF1的核糖体结合,以刺激肽释放和核糖体亚基解离。在此,我们展示了包含eRF1 - eRF3的终止前复合物和包含eRF1 - ABCE1的终止/预循环复合物的冷冻电子显微镜(cryo - EM)结构。eRF1经历了剧烈的构象变化:其包含具有催化重要性的GGQ环的中央结构域,在与eRF3结合时靠在eRF3上,而在与ABCE1结合时则向肽基转移酶中心摆动。此外,在与eRF3形成的复合物中,eRF1的N端结构域将保守的NIKS基序定位在终止密码子附近,支持其在解码中的推测作用,但在ABCE1存在时它似乎会发生位移。这些结果表明,在终止过程中,终止密码子的解码和肽的释放可能是解偶联的。

https://cdn.ncbi.nlm.nih.gov/pmc/blobs/bd99/6813808/c3a31ae996b9/nihms-1054852-f0001.jpg

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