NAD(+)-dependent RNA terminal 2 ' and 3 ' phosphomonoesterase activity of a subset of Tpt1 enzymes Journal Article
| Authors: | Munir, A.; Abdullahu, L.; Banerjee, A.; Damha, M. J.; Shuman, S. |
| Article Title: | NAD(+)-dependent RNA terminal 2 ' and 3 ' phosphomonoesterase activity of a subset of Tpt1 enzymes |
| Abstract: | The enzyme Tpt1 removes the 2′-PO4 at the splice junction generated by fungal tRNA ligase; it does so via a two-step reaction in which (i) the internal RNA 2′-PO4 attacks NAD+ to form an RNA-2′-phospho-ADP-ribosyl intermediate; and (ii) transesterification of the ribose O2′′ to the 2′-phosphodiester yields 2′-OH RNA and ADP-ribose-1′′,2′′-cyclic phosphate products. The role that Tpt1 enzymes play in taxa that have no fungal-type RNA ligase remains obscure. An attractive prospect is that Tpt1 enzymes might catalyze reactions other than internal RNA 2′-PO4 removal, via their unique NAD+-dependent transferase mechanism. This study extends the repertoire of the Tpt1 enzyme family to include the NAD+-dependent conversion of RNA terminal 2′ and 3′ monophosphate ends to 2′-OH and 3′-OH ends, respectively. The salient finding is that different Tpt1 enzymes vary in their capacity and positional specificity for terminal phosphate removal. Clostridium thermocellum and Aeropyrum pernix Tpt1 proteins are active on 2′-PO4 and 3′-PO4 ends, with a 2.4- to 2.6-fold kinetic preference for the 2′-PO4. The accumulation of a terminal 3′-phospho-ADP-ribosylated RNA intermediate during the 3′-phosphotransferase reaction suggests that the geometry of the 3′-p-ADPR adduct is not optimal for the ensuing transesterification step. Chaetomium thermophilum Tpt1 acts specifically on a terminal 2′-PO4 end and not with a 3′-PO4. In contrast, Runella slithyformis Tpt1 and human Tpt1 are ineffective in removing either a 2′-PO4 or 3′-PO4 end. © 2019 Munir et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society. |
| Keywords: | nicotinamide adenine dinucleotide; rna-phospho-adp-ribose intermediate; terminal phosphate removal; rna 2′-phosphotransferase |
| Journal Title: | RNA |
| Volume: | 25 |
| Issue: | 7 |
| ISSN: | 1355-8382 |
| Publisher: | Cold Spring Harbor Laboratory Press |
| Date Published: | 2019-07-01 |
| Start Page: | 783 |
| End Page: | 792 |
| Language: | English |
| DOI: | 10.1261/rna.071142.119 |
| PUBMED: | 31019096 |
| PROVIDER: | scopus |
| PMCID: | PMC6573784 |
| DOI/URL: | |
| Notes: | Article -- Export Date: 2 August 2019 -- Source: Scopus |
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