{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T17:02:02Z","timestamp":1789578122950,"version":"build-2803163510"},"reference-count":0,"publisher":"Cold Spring Harbor Laboratory","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["RNA"],"accepted":{"date-parts":[[2026,9,9]]},"abstract":"<jats:p>RNA 2'-phosphotransferase Tpt1 is a widely distributed enzyme that removes an internal RNA 2'-phosphate by transfer to NAD+. Tpt1 is essential in fungi, where it erases the 2'-PO4 mark installed by tRNA ligase during tRNA splicing. Tpt1 enzymes from bacteria, archaea, fungi, and metazoa are monofunctional units composed of RNA-binding and NAD+-binding lobes. The lone exception to date is fission yeast Tpt1, which consists of an N-terminal RNA 2'-phosphotransferase catalytic domain fused to a C-terminal domain homologous to budding yeast iron-sulfur cluster assembly factor Yae1. Here we report that the Tpt1 homologs of kinetoplastid protozoa are bifunctional enzymes composed of an N-terminal DEDDh-type nuclease domain linked to a C-terminal 2'-phosphotransferase domain. Characterization of Trypanosoma brucei Tpt1 (TbrTpt1) revealed that: (i) the C-terminal domain TbrTpt1-(298-540) is an autonomous module that catalyzes 2'-PO4 transfer to NAD+ via an RNA-2'-phospho-(ADP-ribose) intermediate; (ii) TbrTpt1-(299-540) is active in tRNA splicing in vivo when expressed in budding yeast tpt1\u2206 cells; and (iii) TbrTpt1 is a manganese-dependent 3'-exonuclease adept at resecting DNA and RNA single strands. TbrTpt1\u2019s RNA exonuclease is blocked by a 2' terminal phosphate. TbrTpt1 and TbrTpt1-(298-540) can remove a 2'-terminal phosphate via transfer to NAD+, albeit much less efficiently than removal of an internal 2'-phosphate.<\/jats:p>","DOI":"10.1261\/rna.081235.126","type":"journal-article","created":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T16:05:16Z","timestamp":1789574716000},"page":"rna.081235.126","source":"Crossref","is-referenced-by-count":0,"title":["Trypanosome Tpt1 is a bifunctional enzyme composed of tandem DEDDh nuclease and RNA 2'-phosphotransferase domains"],"prefix":"10.1261","author":[{"given":"Apurba","family":"Sarkar","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shreya","family":"Ghosh","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3824-9819","authenticated-orcid":false,"given":"Beate","family":"Schwer","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5034-6438","authenticated-orcid":false,"given":"Stewart","family":"Shuman","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"246","published-online":{"date-parts":[[2026,9,16]]},"container-title":["RNA"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1261\/rna.081235.126","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T16:05:16Z","timestamp":1789574716000},"score":1,"resource":{"primary":{"URL":"http:\/\/rnajournal.cshlp.org\/lookup\/doi\/10.1261\/rna.081235.126"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,16]]},"references-count":0,"alternative-id":["10.1261\/rna.081235.126"],"URL":"https:\/\/doi.org\/10.1261\/rna.081235.126","relation":{},"ISSN":["1355-8382","1469-9001"],"issn-type":[{"value":"1355-8382","type":"print"},{"value":"1469-9001","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,16]]}}}