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Publication Abstract from PubMed

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.

Structural basis for substrate recognition and processive cleavage mechanisms of the trimeric exonuclease PhoExo I.,Miyazono KI, Ishino S, Tsutsumi K, Ito T, Ishino Y, Tanokura M Nucleic Acids Res. 2015 Jul 2. pii: gkv654. PMID:26138487^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.