Structural requirement for Mg2+ binding in the group I intron core.
Structural requirement for Mg2+ binding in the group I intron core.
复制标题
I 组内含子核心中 Mg2 结合的结构要求。
DOI：
10.1016/s0022-2836(03)00430-3
复制
发表时间：
2003
影响因子：
5.6
通讯作者：
Woodson,SarahA
中科院分区：
文献类型：
--
作者：
Rangan,Prashanth;Woodson,SarahA
Divalent metal ions are required for splicing of group I introns, but their role in maintaining the structure of the active site is still under investigation. Ribonuclease and hydroxyl radical footprinting of a small group I intron from Azoarcus pre-tRNAIleshowed that tertiary interactions between helical domains are stable in a variety of cations. Only Mg2+, however, induced a conformational change in the intron core that correlates with self-splicing activity. Three metal ion binding sites in the catalytic core were identified by Tb(III)-dependent cleavage. Two of these are near bound substrates in a three-dimensional model of the ribozyme. A third metal ion site is near an A minor motif in P3. In the pre-tRNA, Tb3+cleavage was redirected to the 5′ and 3′ splice sites, consistent with metal-dependent activation of splice site phosphodiesters. The results show that many counterions induce global folding, but organization of the group I active site is specifically linked to Mg2+binding at a few sites.
