核酶
四膜虫
活动站点
RNA剪接
鸟苷
哺乳动物CPEB3核酶
结合位点
发夹状核酶
核酶
内含子
立体化学
螺旋(腹足类)
化学
核苷酸
核糖核酸
结晶学
生物
酶
生物化学
基因
蜗牛
生态学
作者
Barbara L. Golden,Anne R. Gooding,Elaine R. Podell,Thomas R. Cech
出处
期刊:Science
[American Association for the Advancement of Science (AAAS)]
日期:1998-10-09
卷期号:282 (5387): 259-264
被引量:315
标识
DOI:10.1126/science.282.5387.259
摘要
Group I introns possess a single active site that catalyzes the two sequential reactions of self-splicing. An RNA comprising the two domains of the Tetrahymena thermophila group I intron catalytic core retains activity, and the 5.0 angstrom crystal structure of this 247-nucleotide ribozyme is now described. Close packing of the two domains forms a shallow cleft capable of binding the short helix that contains the 5′ splice site. The helix that provides the binding site for the guanosine substrate deviates significantly from A-form geometry, providing a tight binding pocket. The binding pockets for both the 5′ splice site helix and guanosine are formed and oriented in the absence of these substrates. Thus, this large ribozyme is largely preorganized for catalysis, much like a globular protein enzyme.
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