I类自我剪接的机制：内部引导序列可通过反式提供。

Winter A J, Groot Koerkamp M J, Tabak H F

E.C. Slater Institute for Biochemical Research, University of Amsterdam, The Netherlands.

EMBO J. 1990 Jun;9(6):1923-8. doi: 10.1002/j.1460-2075.1990.tb08319.x.

We have reconstituted a group I self-splicing reaction between two RNA molecules with different functional RNA parts: a substrate molecule containing the 5' splice site and a functional internal guide sequence (IGS), and a ribozyme molecule with core structure elements and splice sites but a mutated IGS. The 5' exon of the substrate molecule is ligated in trans to the 3' exon of the ribozyme molecule, suggesting that the deficient IGS in the ribozyme can be replaced by an externally added IGS present on the substrate molecule. This result is different from catalysis mediated by proteins where it is not possible to dissect the specificity of an enzyme from its catalytic activity.

我们在两个具有不同功能性RNA部分的RNA分子之间重建了I组自剪接反应：一个底物分子，包含5'剪接位点和一个功能性内部引导序列（IGS），以及一个具有核心结构元件和剪接位点但IGS发生突变的核酶分子。底物分子的5'外显子与核酶分子的3'外显子进行反式连接，这表明核酶中缺陷的IGS可以被底物分子上外部添加的IGS所取代。这一结果与蛋白质介导的催化作用不同，在蛋白质催化中，不可能将酶的特异性与其催化活性分开。