Ribozymes articles from across Nature Portfolio

The diverse functional roles of ribozymes (RNAs with enzymatic activity) continue to be uncovered. Here, the authors identify and characterize a subgroup of minimal hepatitis delta virus (HDV)-like ribozymes – termed Theta ribozymes -, which they show process viral tRNA transcripts, and appearing crucial for lytic gene expression in recoded phages.

The formation of the 2′–5′ lariat bond during branching is the critical first step in RNA splicing. A structure of a group II intron reveals a conserved base triple responsible for positioning the adenosine nucleophile to attack the 5′ splice site.

RNA viruses are defined by linear RNA genomes encoding an RNA-dependent RNA polymerase, while viroid-like elements consist of small, single-stranded, circular RNA genomes that, in some cases, encode self-cleaving catalytic RNAs. Here, the authors identify over 20,000 candidate viroid-like elements, and show that infectious agents of fungi display hybrid features of viroid-like RNAs and RNA viruses.

Low activity currently prevents the wider use of DNA enzymes (DNAzymes). Here the authors report the chemical evolution of a DNAzyme with high catalytic activity under near physiological conditions: the enzyme achieves ~65 turnovers in 30 minutes.

Natural self-cleaving RNAs employ a wide range of catalytic strategies, but it is not known whether artificial ribozymes are capable of the same catalytic diversity. New structures of a methyltransferase ribozyme reveal the potential variety of RNA reactions and mechanisms.

An approach based on enrichment of 5′ hydroxylated RNAs reveals a new self-cleaving ribozyme that maps to a very long non-protein-coding RNA in simians. The ribozyme is active only among hominin sequences, suggesting a recent acquisition of the activity.