Glatt Sebastian, Zabel Rene, Kolaj-Robin Olga, Onuma Osita F, Baudin Florence, Graziadei Andrea, Taverniti Valerio, Lin Ting-Yu, Baymann Frauke, Seraphin Bertrand, Breunig Karin D, Müller Christoph W
European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany.
Max Planck Research Group at the Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland.
Nat Struct Mol Biol. 2016 Sep;23(9):794-802. doi: 10.1038/nsmb.3265. Epub 2016 Jul 25.
During translation elongation, decoding is based on the recognition of codons by corresponding tRNA anticodon triplets. Molecular mechanisms that regulate global protein synthesis via specific base modifications in tRNA anticodons are receiving increasing attention. The conserved eukaryotic Elongator complex specifically modifies uridines located in the wobble base position of tRNAs. Mutations in Elongator subunits are associated with certain neurodegenerative diseases and cancer. Here we present the crystal structure of D. mccartyi Elp3 (DmcElp3) at 2.15-Å resolution. Our results reveal an unexpected arrangement of Elp3 lysine acetyltransferase (KAT) and radical S-adenosyl methionine (SAM) domains, which share a large interface and form a composite active site and tRNA-binding pocket, with an iron-sulfur cluster located in the dimerization interface of two DmcElp3 molecules. Structure-guided mutagenesis studies of yeast Elp3 confirmed the relevance of our findings for eukaryotic Elp3s and should aid in understanding the cellular functions and pathophysiological roles of Elongator.
在翻译延伸过程中，解码基于相应的tRNA反密码子三联体对密码子的识别。通过tRNA反密码子中的特定碱基修饰来调节全局蛋白质合成的分子机制正受到越来越多的关注。保守的真核延伸因子复合物特异性修饰位于tRNA摆动碱基位置的尿苷。延伸因子亚基的突变与某些神经退行性疾病和癌症有关。在此，我们展示了嗜麦糖嗜纤维菌Elp3（DmcElp3）在2.15埃分辨率下的晶体结构。我们的结果揭示了Elp3赖氨酸乙酰转移酶（KAT）和自由基S-腺苷甲硫氨酸（SAM）结构域的意外排列，它们共享一个大界面并形成一个复合活性位点和tRNA结合口袋，一个铁硫簇位于两个DmcElp3分子的二聚化界面中。对酵母Elp3的结构导向诱变研究证实了我们的发现与真核Elp3的相关性，这将有助于理解延伸因子的细胞功能和病理生理作用。
