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Journal Articles Science Year : 2021

Noncanonical DNA polymerization by aminoadenine-based siphoviruses


Bacteriophage genomes harbor the broadest chemical diversity of nucleobases across all life forms. Certain DNA viruses that infect hosts as diverse as cyanobacteria, proteobacteria, and actinobacteria exhibit wholesale substitution of aminoadenine for adenine, thereby forming three hydrogen bonds with thymine and violating Watson-Crick pairing rules. Aminoadenine-encoded DNA polymerases, homologous to the Klenow fragment of bacterial DNA polymerase I that includes 3′-exonuclease but lacks 5′-exonuclease, were found to preferentially select for aminoadenine instead of adenine in deoxynucleoside triphosphate incorporation templated by thymine. Polymerase genes occur in synteny with genes for a biosynthesis enzyme that produces aminoadenine deoxynucleotides in a wide array of Siphoviridae bacteriophages. Congruent phylogenetic clustering of the polymerases and biosynthesis enzymes suggests that aminoadenine has propagated in DNA alongside adenine since archaic stages of evolution.

Dates and versions

pasteur-03228903 , version 1 (18-05-2021)



Valerie Pezo, Faten Jaziri, Pierre-Yves Bourguignon, Dominique Louis, Deborah Jacobs-Sera, et al.. Noncanonical DNA polymerization by aminoadenine-based siphoviruses. Science, 2021, 372 (6541), pp.520-524. ⟨10.1126/science.abe6542⟩. ⟨pasteur-03228903⟩
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