4YOT: Crystal Structure Of A Trimeric Exonuclease Phoexo I From Pyrococcus Horikoshii Ot3 At 2.15a Resolution

Nucleases play important roles in nucleic acid processes, such as replication, repair and recombination. Recently, we identified a novel single-strand specific 3'-5' exonuclease, PfuExo I, from the hyperthermophilic archaeon Pyrococcus furiosus, which may be involved in the Thermococcales-specific DNA repair system. PfuExo I forms a trimer and cleaves single-stranded DNA at every two nucleotides. Here, we report the structural basis for the cleavage mechanism of this novel exonuclease family. A structural analysis of PhoExo I, the homologous enzyme from P. horikoshii OT3, showed that PhoExo I utilizes an RNase H-like active site and possesses a 3'-OH recognition site approximately 9 A away from the active site, which enables cleavage at every two nucleotides. Analyses of the heterotrimeric and monomeric PhoExo I activities showed that trimerization is indispensable for its processive cleavage mechanism, but only one active site of the trimer is required.
PDB ID: 4YOTDownload
MMDB ID: 130968
PDB Deposition Date: 2015/3/12
Updated in MMDB: 2015/09
Experimental Method:
x-ray diffraction
Resolution: 2.15  Å
Source Organism:
Similar Structures:
Biological Unit for 4YOT: trimeric; determined by author and by software (PISA)
Molecular Components in 4YOT
Label Count Molecule
Proteins (3 molecules)
3-5 Exonuclease Phoexo I
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB