A mutation in polynucleotide phosphorylase from Escherichia coli impairing RNA binding and degradosome stability.

ABSTRACT: Polynucleotide phosphorylase (PNPase), a 3' to 5' exonuclease encoded by pnp, plays a key role in Escherichia coli RNA decay. The enzyme, made of three identical 711 amino acid subunits, may also be assembled in the RNA degradosome, a heteromultimeric complex involved in RNA degradation. PNPase autogenously regulates its expression by promoting the decay of pnp mRNA, supposedly by binding at the 5'-untranslated leader region of an RNase III-processed form of this transcript. The KH and S1 RNA-binding domains at the C-terminus of the protein (amino acids 552-711) are thought to be involved in pnp mRNA recognition. Here we show that a G454D substitution in E.coli PNPase impairs autogenous regulation whereas it does not affect the catalytic activities of the enzyme. Although the mutation maps

SUBMITTER: Regonesi ME 

PROVIDER: S-EPMC373403 | biostudies-literature | 2004

REPOSITORIES: biostudies-literature