biostudies-literatureUnknown45(3)Poudyal RRRibozymes can catalyze phosphoryl or nucleotidyl transfer onto ribose hydroxyls of RNA chains. We report a single ribozyme that performs both reactions, with a nucleobase serving as initial acceptor moiety. This unprecedented combined reaction was revealed while investigating potential contributions of ribose hydroxyls to catalysis by kinase ribozyme K28. For a 58nt, cis-acting form of K28, each nucleotide could be replaced with the corresponding 2΄F analog without loss of activity, indicating that no particular 2΄OH is specifically required. Reactivities of two-stranded K28 variants with oligodeoxynucleotide acceptor strands devoid of any 2΄OH moieties implicate modification on an internal guanosine N-2, rather than a ribose hydroxyl. Product mass suggests formation of a GDP(S) adduct aloNucleic acids research1345-1354https://www.ebi.ac.uk/biostudies/studies/S-EPMC5388400biostudies-literatureNucleobase modification by an RNA enzyme.PMC5388400Poudyal RRCallaway MKNguyen PDKrishnamurthy RBurke DHLokugamage MPGavette JVfalseNucleobase modification by an RNA enzyme.Ribozymes can catalyze phosphoryl or nucleotidyl transfer onto ribose hydroxyls of RNA chains. We report a single ribozyme that performs both reactions, with a nucleobase serving as initial acceptor moiety. This unprecedented combined reaction was revealed while investigating potential contributions of ribose hydroxyls to catalysis by kinase ribozyme K28. For a 58nt, cis-acting form of K28, each nucleotide could be replaced with the corresponding 2΄F analog without loss of activity, indicating that no particular 2΄OH is specifically required. Reactivities of two-stranded K28 variants with oligodeoxynucleotide acceptor strands devoid of any 2΄OH moieties implicate modification on an internal guanosine N-2, rather than a ribose hydroxyl. Product mass suggests formation of a GDP(S) adduct alo2017-01-01T00:00:00Z2017 Feb2025-04-04T14:32:51.033Z2019-03-27T02:41:03ZS-EPMC53884002818030210.1093/nar/gkw1199