Site-specific ribonuclease activity of eukaryotic DNA topoisomerase I Journal Article
| Authors: | Sekiguchi, J.; Shuman, S. |
| Article Title: | Site-specific ribonuclease activity of eukaryotic DNA topoisomerase I |
| Abstract: | Type I topoisomerases alter DN A topology by cleaving and rejoining one strand of duplex DNA through a covalent protein-DNA intermediate. Here we show that vaccinia topoisomerase, a eukaryotic type IB enzyme, catalyzes site-specific endoribonucleolytic cleavage of an RNA-containing strand. The RNase reaction occurs via transesterification at the scissile ribonucleotide to form a covalent RNA-3′-phosphoryl-enzyme intermediate, which is then attacked by the vicinal 2′ OH of the ribose sugar to yield a free 2′, 3′ cyclic phosphate product. Introduction of a single ribonucleoside at the scissile phosphate of an otherwise all-DMA substrate suffices to convert the topoisomerase into an endonuclease. Human topoisomerase I also has endoribonuclease activity. These findings suggest potential roles for topoisomerases in RNA processing. |
| Keywords: | genetics; molecular genetics; metabolism; enzymology; tyrosine; physiology; dna; molecular sequence data; kinetics; messenger rna; rna, messenger; nucleotide sequence; substrate specificity; vaccinia virus; base sequence; eukaryotic cell; enzyme specificity; phosphate; phosphates; uridine; ribonucleases; thymidine; dna topoisomerase; dna topoisomerases, type i; ribonuclease; eukaryotic cells; humans; human; article |
| Journal Title: | Molecular Cell |
| Volume: | 1 |
| Issue: | 1 |
| ISSN: | 1097-2765 |
| Publisher: | Cell Press |
| Date Published: | 1997-12-01 |
| Start Page: | 89 |
| End Page: | 97 |
| Language: | English |
| PUBMED: | 9659906 |
| PROVIDER: | scopus |
| DOI: | 10.1016/S1097-2765(00)80010-6 |
| DOI/URL: | |
| Notes: | Article -- Export Date: 17 March 2017 -- Source: Scopus |
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