Selective 8-oxo-rG stalling occurs in the catalytic core of polynucleotide phosphorylase (PNPase) during degradation.

ABSTRACT: RNA oxidation, predominantly through the accumulation of 8-oxo-7,8-dihydroguanosine (8-oxo-rG), represents an important biomarker for cellular oxidative stress. Polynucleotide phosphorylase (PNPase) is a 3'-5' exoribonuclease that has been shown to preferentially recognize 8-oxo-rG-containing RNA and protect Escherichia coli cells from oxidative stress. However, the impact of 8-oxo-rG on PNPase-mediated RNA degradation has not been studied. Here, we show that the presence of 8-oxo-rG in RNA leads to catalytic stalling of E. coli PNPase through in vitro RNA degradation experiments and electrophoretic analysis. We also link this stalling to the active site of the enzyme through resolution of single-particle cryo-EM structures for PNPase in complex with singly or doubly o

SUBMITTER: Miller LG 

PROVIDER: S-EPMC11572968 | biostudies-literature | 2024 Nov

REPOSITORIES: biostudies-literature