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Molecular Basis of Substrate Recognition of Endonuclease Q from the Euryarchaeon Pyrococcus furiosus.

DOI： 10.1128/JB.00542-19

Language：Others  

The mesophilic archaeon Methanosarcina acetivorans counteracts uracil in DNA with multiple enzymes: EndoQ, ExoIII, and UDG.

DOI： 10.1038/s41598-018-34000-x

Language：Others  

Fluorescence detection of DNA mismatch repair in human cells.

DOI： 10.1038/s41598-018-30733-x

Language：English   Publishing type：Research paper (scientific journal)  

DNA base deamination occurs spontaneously under physiological conditions and is promoted by high temperature. Therefore, hyperthermophiles are expected to have efficient repair systems of the deaminated bases in their genomes. Endonuclease Q (EndoQ) was originally identified from the hyperthermophlic archaeon, Pyrococcus furiosus, as a hypoxanthine-specific endonuclease recently. Further biochemical analyses revealed that EndoQ also recognizes uracil, xanthine, and the AP site in DNA, and is probably involved in a specific repair process for damaged bases. Initial phylogenetic analysis showed that an EndoQ homolog is found only in the Thermococcales and some of the methanogens in Archaea, and is not present in most members of the domains Bacteria and Eukarya. A better understanding of the distribution of the EndoQ-mediated repair system is, therefore, of evolutionary interest. We showed here that an EndoQ-like polypeptide from Bacillus pumilus, belonging to the bacterial domain, is functional and has similar properties with the archaeal EndoQs.

DOI： 10.1080/09168451.2016.1277946

Language：English   Publishing type：Research paper (scientific journal)  

To maintain genome integrity for transfer to their offspring, and to maintain order in cellular processes, all living organisms have DNA repair systems. Besides the well-conserved DNA repair machineries, organisms thriving in extreme environments are expected to have developed efficient repair systems. We recently discovered a novel endonuclease, which cleaves the 5' side of deoxyinosine, from the hyperthermophilic archaeon, Pyrococcus furiosus. The novel endonuclease, designated as Endonulcease Q (EndoQ), recognizes uracil, abasic site and xanthine, as well as hypoxanthine, and cuts the phosphodiester bond at their 5' sides. To understand the functional process involving EndoQ, we searched for interacting partners of EndoQ and identified Proliferating Cell Nuclear Angigen (PCNA). The EndoQ activity was clearly enhanced by addition of PCNA in vitro. The physical interaction between the two proteins through a PIP-motif of EndoQ and the toroidal structure of PCNA are critical for the stimulation of the endonuclease activity. These findings provide us a clue to elucidate a unique DNA repair system in Archaea.

DOI： 10.1038/srep25532

Language：English   Publishing type：Research paper (scientific journal)  

Base deamination is a typical form of DNA damage, and it must be repaired quickly to maintain the genome integrity of living organisms. Endonuclease Q (EndoQ), recently found in the hyperthermophilic archaea, is an enzyme that cleaves the phosphodiester bond 5' from the damaged nucleotide in the DNA strand, and may primarily function to start the repair process for the damaged bases. Endonuclease V (EndoV) also hydrolyzes the second phosphodiester bond 3' from the damaged nucleotide, although the hyperthermophilic archaeal EndoV is a strictly hypoxanthine-specific endonuclease. To understand the relationships of the EndoQ and EndoV functions in hyperthermophilic archaea, we analyzed their interactions in hypoxanthine repair. EndoQ and EndoV do not directly interact with each other in either the presence or absence of DNA. However, EndoQ and EndoV individually worked on deoxyinosine (dl)-containing DNA at each cleavage site. EndoQ has higher affinity to dl-containing DNA than EndoV, and cells produce higher amounts of EndoQ as compared to EndoV. These data support the proposal that EndoQ primarily functions for, at least, dl-containing DNA. (C) 2015 Elsevier B.V. and Societe Francaise de Biochimie et Biologie Moleculaire (SFBBM). All rights reserved.

DOI： 10.1016/j.biochi.2015.06.015

Language：English   Publishing type：Research paper (scientific journal)  

DNA is constantly damaged by endogenous and environmental influences. Deaminated adenine (hypoxanthine) tends to pair with cytosine and leads to the A:T -> G:C transition mutation during DNA replication. Endonuclease V (EndoV) hydrolyzes the second phosphodiester bond 3 ' from deoxyinosine in the DNA strand, and was considered to be responsible for hypoxanthine excision repair. However, the downstream pathway after EndoV cleavage remained unclear. The activity to cleave the phosphodiester bond 5 ' from deoxyinosine was detected in a Pyro-coccus furiosus cell extract. The protein encoded by PF1551, obtained from the mass spectrometry analysis of the purified fraction, exhibited the corresponding cleavage activity. A putative homolog from Thermococcus kodakarensis (TK0887) showed the same activity. Further biochemical analyses revealed that the purified PF1551 and TK0887 proteins recognize uracil, xanthine and the AP site, in addition to hypoxanthine. We named this endonuclease Endonuclease Q (EndoQ), as it may be involved in damaged base repair in the Thermococcals of Archaea.

DOI： 10.1093/nar/gkv121

Repository Public URL： https://hdl.handle.net/2324/7183344

Language：English  

Country：Other  

A Novel DNA Repair Pathway for Damaged Bases in Thermococcales

Language：English  

Country：Other  

Endonuclease Q Acts on Various Mutagenic Bases in Hyperthermophilic Archaea

Language：English  

Country：Other  

Substrate recognition mechanisms of Endonuclease Q from the euryarchaeon Pyrococcus furiosus

Language：Others  

Country：Other  

Language：Others  

Country：Other  

Characterization of archaeal Endonuclease V

Language：Others  

Country：Other  

Language：Others  

Country：Other  

Elucidation of mechanism for chromatin regulation by Cdt1 and Cdt1-interacting chromatin handling factors

Language：Others  

Country：Other  

Current understanding of DNA repair mechanisms in archaea

Language：Others  

Country：Other  

Language：Others  

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Presentation type：Symposium, workshop panel (nominated)  

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Presentation type：Poster presentation  

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