Distinct roles for CTD Ser-2 and Ser-5 phosphorylation in the recruitment and allosteric activation of mammalian mRNA capping enzyme
Distinct roles for CTD Ser-2 and Ser-5 phosphorylation in the recruitment and allosteric activation of mammalian mRNA capping enzyme
复制标题
DOI：
10.1016/s1097-2765(00)80468-2
复制
发表时间：
1999-03-01
期刊：
影响因子：
16
通讯作者：
Shuman, S
中科院分区：
文献类型：
--
作者：
Ho, CK;Shuman, S
通过加帽装置的鸟苷基转移酶成分与 RNA 聚合酶 II 的磷酸化 CTD 结合，加帽靶向前 mRNA。我们报道哺乳动物鸟苷酸转移酶结合在 YSPTSPS 七肽重复序列的 2 或 5 位上含有磷酸丝氨酸的合成 CTD 肽。含有 Ser-5-PO4 的 CTD 肽通过增强酶对 GTP 的亲和力并增加酶-GMP 中间体的产量来刺激鸟苷酸转移酶活性。含有 Ser-2-PO4 的 CTD 肽对鸟苷酸转移酶活性没有影响。这意味着鸟苷酸转移酶构象发生了变构变化，这种变化是由 CTD 中磷酸丝氨酸的位置决定的。鸟苷酸转移酶的刺激随着 Ser-5-磷酸化七肽的数量而增加。我们的结果强调了在转录延伸过程中如何通过显示不同的 CTD 磷酸化阵列来调节 mRNA 的产生。
Capping is targeted to pre-mRNAs through binding of the guanylyltransferase component of the capping apparatus to the phosphorylated CTD of RNA polymerase II. We report that mammalian guanylyltransferase binds synthetic CTD peptides containing phosphoserine at either position 2 or 5 of the YSPTSPS heptad repeat. CTD peptides containing Ser-5-PO4 stimulate guanylyltransferase activity by enhancing enzyme affinity for GTP and increasing the yield of the enzyme-GMP intermediate. A CTD peptide containing Ser-2-PO4 has no effect on guanylyltransferase activity. This implies an allosteric change in guanylyltransferase conformation that is specified by the position of phosphoserine in the CTD. Stimulation of guanylyltransferase increases with the number of Ser-5-phosphorylated heptads. Our results underscore how mRNA production may be regulated by the display of different CTD phosphorylation arrays during transcription elongation.