核酶
内含子
剪接体
RNA剪接
哺乳动物CPEB3核酶
四膜虫
核糖核酸
第二组内含子
核苷酸
发夹状核酶
结晶学
化学
生物
立体化学
生物化学
基因
作者
Jamie H. D. Cate,Anne R. Gooding,Elaine R. Podell,Keming Zhou,Barbara L. Golden,Craig E. Kundrot,Thomas R. Cech,Jennifer A. Doudna
出处
期刊:Science
[American Association for the Advancement of Science (AAAS)]
日期:1996-09-20
卷期号:273 (5282): 1678-1685
被引量:1234
标识
DOI:10.1126/science.273.5282.1678
摘要
Group I self-splicing introns catalyze their own excision from precursor RNAs by way of a two-step transesterification reaction. The catalytic core of these ribozymes is formed by two structural domains. The 2.8-angstrom crystal structure of one of these, the P4-P6 domain of the Tetrahymena thermophila intron, is described. In the 160-nucleotide domain, a sharp bend allows stacked helices of the conserved core to pack alongside helices of an adjacent region. Two specific long-range interactions clamp the two halves of the domain together: a two-Mg 2+ -coordinated adenosine-rich corkscrew plugs into the minor groove of a helix, and a GAAA hairpin loop binds to a conserved 11-nucleotide internal loop. Metal- and ribose-mediated backbone contacts further stabilize the close side-by-side helical packing. The structure indicates the extent of RNA packing required for the function of large ribozymes, the spliceosome, and the ribosome.
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