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

摘要: Cytosine deamination into uracil is one of the most prevalent and pro-mutagenic forms damage to DNA. Base excision repair a well-known process removal in DNA, which achieved by DNA glycosylase (UDG) that found all three domains life. However, other strategies for seem have been evolved Archaea. Exonuclease III (ExoIII) from euryarchaeon Methanothermobacter thermautotrophicus has described exhibit endonuclease activity toward uracil-containing Another uracil-acting protein, Q (EndoQ), was recently identified Pyrococcus furiosus. Here, we describe uracil-counteracting system mesophilic Methanosarcina acetivorans through genomic sequence analyses biochemical characterizations. Three enzymes, UDG, ExoIII, EndoQ, M. exhibited cleavage activities with distinct range substrate specificities vitro, transcripts these enzymes were detected cells. Thus, this organism appears conduct using at least pathways. Distribution homologs uracil-targeting proteins Archaea showed tendency not restricted acetivorans, but diverse This work further underscores importance uracil-removal systems maintain genome integrity Archaea, including ‘UDG lacking’ organisms.