Insight into the mechanism of nonenzymatic RNA primer extension from the structure of an RNA-GpppG complex.

ABSTRACT: The nonenzymatic copying of RNA templates with imidazole-activated nucleotides is a well-studied model for the emergence of RNA self-replication during the origin of life. We have recently discovered that this reaction can proceed through the formation of an imidazolium-bridged dinucleotide intermediate that reacts rapidly with the primer. To gain insight into the relationship between the structure of this intermediate and its reactivity, we cocrystallized an RNA primer-template complex with a close analog of the intermediate, the triphosphate-bridged guanosine dinucleotide GpppG, and solved a high-resolution X-ray structure of the complex. The structure shows that GpppG binds the RNA template through two Watson-Crick base pairs, with the primer 3'-hydroxyl oriented to attack the 5'-phosph

SUBMITTER: Zhang W 

PROVIDER: S-EPMC5530681 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature