Merits A, Kettunen R, Mäkinen K, Lampio A, Auvinen P, Kääriäinen L, Ahola T
Institute of Biotechnology, Biocenter Viikki, University of Helsinki, Finland.
FEBS Lett. 1999 Jul 16;455(1-2):45-8. doi: 10.1016/s0014-5793(99)00856-x.
In capping cellular mRNAs, a covalent GMP-enzyme intermediate leads to formation of G(5')ppp(5')N at the 5' end of the RNA, which is modified by methylation catalyzed by guanine-7-methyltransferase. Here we show that isolated membranes from tobacco mosaic virus (TMV)-infected plant or insect cells expressing TMV replicase protein p126, synthesized m7GTP using S-adenosylmethionine (AdoMet) as the methyl donor, and catalyzed the formation of a covalent guanylate-p126 complex in the presence of AdoMet. The methyl group from AdoMet was incorporated into p126, suggesting that the complex consisted of m7GMP-p126. Thus, TMV and alphaviruses, despite their evolutionary distance, share the same virus-specific capping mechanism.
在对细胞mRNA进行加帽时，一种共价GMP-酶中间体导致在RNA的5'端形成G(5')ppp(5')N，其由鸟嘌呤-7-甲基转移酶催化的甲基化修饰。在此我们表明，从感染烟草花叶病毒（TMV）的植物或表达TMV复制酶蛋白p126的昆虫细胞中分离出的膜，以S-腺苷甲硫氨酸（AdoMet）作为甲基供体合成了m7GTP，并在AdoMet存在的情况下催化形成共价鸟苷酸-p126复合物。来自AdoMet的甲基被掺入p126中，这表明该复合物由m7GMP-p126组成。因此，尽管TMV和甲病毒在进化上有距离，但它们共享相同的病毒特异性加帽机制。
