Publication Date:
2018-03-19
Description:
Certain viruses of bacteria (bacteriophages) enzymatically hypermodify their DNA to protect their genetic material from host restriction endonuclease-mediated cleavage. Historically, it has been known that virion DNAs from theDelftiaphage ΦW-14 and theBacillusphage SP10 contain the hypermodified pyrimidines α-putrescinylthymidine and α-glutamylthymidine, respectively. These bases derive from the modification of 5-hydroxymethyl-2′-deoxyuridine (5-hmdU) in newly replicated phage DNA via a pyrophosphorylated intermediate. Like ΦW-14 and SP10, thePseudomonasphage M6 and theSalmonellaphage ViI encode kinase homologs predicted to phosphorylate 5-hmdU DNA but have uncharacterized nucleotide content [Iyer et al. (2013)Nucleic Acids Res41:7635–7655]. We report here the discovery and characterization of two bases, 5-(2-aminoethoxy)methyluridine (5-NeOmdU) and 5-(2-aminoethyl)uridine (5-NedU), in the virion DNA of ViI and M6 phages, respectively. Furthermore, we show that recombinant expression of five gene products encoded by phage ViI is sufficient to reconstitute the formation of 5-NeOmdU in vitro. These findings point to an unexplored diversity of DNA modifications and the underlying biochemistry of their formation.
Print ISSN:
0027-8424
Electronic ISSN:
1091-6490
Topics:
Biology
,
Medicine
,
Natural Sciences in General
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