Structural and biochemical studies of the 5'→3' exoribonuclease Xrn1.

ABSTRACT: The 5'→3' exoribonucleases (XRNs) have important functions in transcription, RNA metabolism and RNA interference. The structure of Rat1 (also known as Xrn2) showed that the two highly conserved regions of XRNs form a single, large domain that defines the active site of the enzyme. Xrn1 has a 510-residue segment after the conserved regions that is required for activity but is absent from Rat1/Xrn2. Here we report the crystal structures of Kluyveromyces lactis Xrn1 (residues 1-1,245, E178Q mutant), alone and in complex with a Mn(2+) ion in the active site. The 510-residue segment contains four domains (D1-D4), located far from the active site. Our mutagenesis and biochemical studies show that their functional importance results from their ability to stabilize the conformation of the N-termin

SUBMITTER: Chang JH 

PROVIDER: S-EPMC3075561 | biostudies-literature | 2011 Mar

REPOSITORIES: biostudies-literature