Accumulation of a “DNA-Masking Protein” in E. coli under Inhibitory Conditions of DNA Synthesis
1972 年 71 巻 3 号 p. 497-505
詳細
1972 年 71 巻 3 号 p. 497-505
Inhibition of DNA synthesis by thymine-starvation causes an accumulation of a peculiar protein in cells of Eschcrichia coli. When mixed with the protein in the cold, single-stranded DNA of φX174 or φA rapidly loses the infectivity to bacterial spheroplasts: susceptibility to endonuclease I is also reduced considerably. Partial restoration of the infectivity is observed after incubating the mixture at 37°C. The biological activity of DNA is more effectively recovered either by phenol extraction or by protease-treatment of the mixture, showing that the loss of infectivity is due to a masking rather than permanent changes of DNA structure. The DNA-masking activity is detected also in cells treated with DNA-synthesis inhibitor such as nalidixic acid or nitrofuran derivatives. Some properties of the masking-protein together with the effect on infectivity of MS 2 RNA and φA replicative form DNA are investigated and the possible role of the protein in nucleic acid metabolism is discussed.
