Capping of tobacco mosaic virus RNA. Analysis of viral-coded guanylyltransferase-like activity.
نویسندگان
چکیده
The 5' end of tobacco mosaic virus (TMV) genomic RNA is capped with 7-methylguanosine. A virus-coded polypeptide with guanylyltransferase activity has been investigated. This enzyme is responsible for forming the 5'----5' linkage of guanosine 5'-monophosphate to the 5'-diphosphate of an acceptor RNA, thereby forming the cap. A critical step in the mechanism for cap formation in the eukaryotic nucleus is for guanylyltransferase to bind covalently to guanosine 5'-monophosphate with the hydrolysis of pyrophosphate when guanosine 5'-triphosphate is the substrate. The TMV 126-kilodalton protein, which is most probably a component of the TMV replicase, was found to have this activity. The mechanism of this reaction has been characterized biochemically.
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عنوان ژورنال:
- The Journal of biological chemistry
دوره 265 14 شماره
صفحات -
تاریخ انتشار 1990