Structures of RNA phosphotransferase Tpt1 reveal distinct binding modes for an RNA 2′-PO(4) splice junction versus a 5′-PO(4) mononucleotide Journal Article


Authors: Jacewicz, A.; Damha, M. J.; Shuman, S.
Article Title: Structures of RNA phosphotransferase Tpt1 reveal distinct binding modes for an RNA 2′-PO(4) splice junction versus a 5′-PO(4) mononucleotide
Abstract: Tpt1 is a widely distributed enzyme that removes an internal RNA 2 '-phosphate by transfer to NAD+, via a two-step reaction in which: (i) the RNA 2 '-PO4 attacks NAD+ to form an RNA-2 '-phospho-(ADP-ribose) intermediate and expel nicotinamide; and (ii) the ADP-ribose O2 '' attacks the RNA 2 '-phosphodiester to form 2 '-OH RNA and ADP-ribose-1 '',2 ''-cyclic phosphate products. Tpt1 can also execute a single-step ADP-ribosyltransferase reaction at a 5 '-monophosphate nucleic acid terminus that installs a 5 '-phospho-ADP-ribose cap structure. Here we present crystal structures of Tpt1 bound to an RNA containing an internal 2 '-PO4 mark (the substrate for the canonical Tpt1 pathway) and in a complex with 5 '-AMP. We find that Tpt1 has distinct binding modes, whereby the RNA 2 '-PO4 and the AMP 5 '-PO4 are engaged by the same set of active site amino acids, but the 2 '-PO4 nucleoside and the 5 '-nucleoside occupy different sites on the enzyme.
Keywords: trna splicing; nicotinamide adenine dinucleotide; enzyme; saccharomyces-cerevisiae; adp-ribosylation; ligated transfer-rna; 2'-phosphotransferase; adp-ribosyl transfer
Journal Title: RNA
Volume: 31
Issue: 7
ISSN: 1355-8382
Publisher: Cold Spring Harbor Laboratory Press  
Date Published: 2025-08-01
Start Page: 916
End Page: 922
Language: English
ACCESSION: WOS:001509425000001
DOI: 10.1261/rna.080444.125
PROVIDER: wos
PMCID: PMC12170183
PUBMED: 40324821
Notes: The MSK Cancer Center Support Grant (P30 CA008748) is acknowledged in the PubMed record and PDF. Corresponding MSK author is Stewart Shuman -- Source: Wos
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  1. Stewart H Shuman
    547 Shuman