title: Archaeal DNA Polymerase-B as a DNA Template Guardian: Links between Polymerases and Base/Alternative Excision Repair Enzymes in Handling the Deaminated Bases Uracil and Hypoxanthine.
abstract: In Archaea repair of uracil and hypoxanthine, which arise by deamination of cytosine and adenine, respectively, is initiated by three enzymes: Uracil-DNA-glycosylase (UDG, which recognises uracil); Endonuclease V (EndoV, which recognises hypoxanthine); and Endonuclease Q (EndoQ), (which recognises both uracil and hypoxanthine). Two archaeal DNA polymerases, Pol-B and Pol-D, are inhibited by deaminated bases in template strands, a feature unique to this domain. Thus the three repair enzymes and the two polymerases show overlapping specificity for uracil and hypoxanthine. Here it is demonstrated that binding of Pol-D to primer-templates containing deaminated bases inhibits the activity of UDG, EndoV, and EndoQ. Similarly Pol-B almost completely turns off EndoQ, extending earlier work that demonstrated that Pol-B reduces catalysis by UDG and EndoV. Pol-B was observed to be a more potent inhibitor of the enzymes compared to Pol-D. Although Pol-D is directly inhibited by template strand uracil, the presence of Pol-B further suppresses any residual activity of Pol-D, to near-zero levels. The results are compatible with Pol-D acting as the replicative polymerase and Pol-B functioning primarily as a guardian preventing deaminated base-induced DNA mutations.
authors.affiliation: Institute of Cell and Molecular Biology (ICaMB), University of Newcastle, Newcastle upon Tyne NE2 4HH, UK.
authors.forename: Javier
authors.identifier: 0000-0001-7342-5286
authors.initials: J
authors.lastname: Abellón-Ruiz
authors.affiliation: Department of Bioscience and Biotechnology, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Sonoko
authors.initials: S
authors.lastname: Ishino
authors.affiliation: Department of Bioscience and Biotechnology, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Yoshizumi
authors.identifier: 0000-0001-9419-0826
authors.initials: Y
authors.lastname: Ishino
authors.affiliation: Institute of Cell and Molecular Biology (ICaMB), University of Newcastle, Newcastle upon Tyne NE2 4HH, UK.
authors.forename: Bernard A
authors.initials: BA
authors.lastname: Connolly
mesh_terms: D001105:Archaea / Q000201:enzymology* / Q000378:metabolism*; D004260:DNA Repair; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D004720:Endonucleases / Q000037:antagonists & inhibitors; D019271:Hypoxanthine / Q000378:metabolism*; D014498:Uracil / Q000378:metabolism*
chemical_list: D019271:Hypoxanthine; D014498:Uracil; D004259:DNA-Directed DNA Polymerase; D004720:Endonucleases