Abstract
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.
Original language | English (US) |
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Pages (from-to) | 7779-7786 |
Number of pages | 8 |
Journal | Journal of Biological Chemistry |
Volume | 265 |
Issue number | 14 |
State | Published - May 15 1990 |
Externally published | Yes |
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology