Xue Song, Calvin Kate, Li Hong
Department of Chemistry and Biochemistry, Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA.
Science. 2006 May 12;312(5775):906-10. doi: 10.1126/science.1126629.
The RNA splicing endonuclease cleaves two phosphodiester bonds within folded precursor RNAs during intron removal, producing the functional RNAs required for protein synthesis. Here we describe at a resolution of 2.85 angstroms the structure of a splicing endonuclease from Archaeglobus fulgidus bound with a bulge-helix-bulge RNA containing a noncleaved and a cleaved splice site. The endonuclease dimer cooperatively recognized a flipped-out bulge base and stabilizes sharply bent bulge backbones that are poised for an in-line RNA cleavage reaction. Cooperativity arises because an arginine pair from one catalytic domain sandwiches a nucleobase within the bulge cleaved by the other catalytic domain.
RNA剪接内切核酸酶在去除内含子时会切割折叠的前体RNA中的两个磷酸二酯键，产生蛋白质合成所需的功能性RNA。在此，我们以2.85埃的分辨率描述了来自嗜热栖热菌的剪接内切核酸酶与包含一个未切割和一个已切割剪接位点的凸起-螺旋-凸起RNA结合的结构。该内切核酸酶二聚体协同识别一个翻转的凸起碱基，并稳定急剧弯曲的凸起主链，这些主链为线性RNA切割反应做好了准备。协同作用的产生是因为来自一个催化结构域的一对精氨酸夹住了由另一个催化结构域切割的凸起内的一个核碱基。
