Deazaguanine derivatives, examples of crosstalk between RNA and DNA modification pathways

ABSTRACT

Seven-deazapurine modifications were thought to be highly specific of tRNAs, but have now been discovered in DNA of phages and of phylogenetically diverse bacteria, illustrating the plasticity of these modification pathways. The intermediate 7-cyano-7-deazaguanine (preQ₀) is a shared precursor in the pathways leading to the insetion of 7-deazapurine derivatives in both tRNA and DNA. It is also used as an intermediate in the synthesis of secondary metabolites such as toyocamacin. The presence of 7-deazapurine in DNA is proposed to be a protection mechanism against endonucleases. This makes preQ₀ a metabolite of underappreaciated but central importance.

KEYWORDS:

• Deazaguanine modifications
• DNA
• tRNA

Disclosure of potential conflicts of interest

No potential conflicts of interest were disclosed.

Acknowledgments

We thank Dirk Iwata-Reuyl for sharing unpublished results and Rémi Zallot for editing the manuscript.

Funding

This work was supported by the National Institutes of Health (grant number R01 GM70641 to V.d.C.-L.)