Myers Christopher A, Kuhla Birte, Cusack Stephen, Lambowitz Alan M
Institute for Cellular and Molecular Biology, Department of Chemistry and Biochemistry, and Section of Molecular Genetics and Microbiology, School of Biological Sciences, University of Texas, Austin, TX 78712, USA.
Proc Natl Acad Sci U S A. 2002 Mar 5;99(5):2630-5. doi: 10.1073/pnas.052596299. Epub 2002 Feb 19.
The Neurospora crassa mitochondrial tyrosyl-tRNA synthetase (CYT-18 protein) functions in splicing group I introns by promoting the formation of the catalytically active RNA structure. Previous work suggested that CYT-18 recognizes a conserved tRNA-like structure of the group I intron catalytic core. Here, directed hydroxyl-radical cleavage assays show that the nucleotide-binding fold and C-terminal domains of CYT-18 interact with the expected group I intron cognates of the aminoacyl-acceptor stem and D-anticodon arms, respectively. Further, three-dimensional graphic modeling, supported by biochemical data, shows that conserved regions of group I introns can be superimposed over interacting regions of the tRNA in a Thermus thermophilus TyrRS/tRNA(Tyr) cocrystal structure. Our results support the hypothesis that CYT-18 and other aminoacyl-tRNA synthetases interact with group I introns by recognizing conserved tRNA-like structural features of the intron RNAs.
粗糙脉孢菌线粒体酪氨酰 - tRNA合成酶(CYT - 18蛋白)通过促进具有催化活性的RNA结构的形成,在I组内含子剪接中发挥作用。先前的研究表明,CYT - 18识别I组内含子催化核心的保守tRNA样结构。在此,定向羟基自由基切割试验表明,CYT - 18的核苷酸结合结构域和C末端结构域分别与氨酰 - 受体茎和D - 反密码子臂的预期I组内含子同源物相互作用。此外,由生化数据支持的三维图形建模表明,I组内含子的保守区域可以叠加在嗜热栖热菌酪氨酰 - tRNA合成酶/Tyr tRNA共晶体结构中tRNA的相互作用区域上。我们的结果支持这样的假设,即CYT - 18和其他氨酰 - tRNA合成酶通过识别内含子RNA的保守tRNA样结构特征与I组内含子相互作用。