Studies on the Biosynthesis of α-Putrescinylthymine in Bacteriophage ΦW-14-Infected Pseudomonas acidovorans

摘要

The α-putrescinylthymine (putThy) in bacteriophage ΦW-14 DNA is synthesized at the mononucleotide level: it is labeled by uracil or deoxyuridine but not by thymidine, and it appears in the acid-soluble pool of infected cells before the onset of phage DNA synthesis. The methylene group at the C-5 position of the pyrimidine moiety of putThy is derived in vivo from a C₁ unit. Extracts of a phage infected thymidine auxotroph of the host, Pseudomonas acidovorans, apparently contain a phage-specific thymidylate synthetase and a phage-specific activity which forms 5-hydroxymethyl dUMP from N₅, N₁₀-methylene-tetrahydrofolate and dUMP.