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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

Lookup NU author(s): Dr Javier Abellon-RuizORCiD, Professor Bernard Connolly



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


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.

Publication metadata

Author(s): Abellon-Ruiz J, Ishino S, Ishino Y, Connolly BA

Publication type: Article

Publication status: Published

Journal: Archaea

Year: 2016

Volume: 2016

Online publication date: 19/09/2016

Acceptance date: 01/08/2016

Date deposited: 13/12/2016

ISSN (print): 1472-3646

ISSN (electronic): 1472-3654

Publisher: Hindawi Publishing Corporation


DOI: 10.1155/2016/1510938


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Funder referenceFunder name
Institute for Fermentation, Osaka (IFO), Japan
26242075Japan MEXT
BB/K005359/1UK BBSRC