Non-glucosylated (Glu-) T-even phage DNAs (hydroxymethylated DNAs) are restricted by E. coli RglA and RglB endonucleases with different specificities. RglB endonuclease is known to be strongly inhibited by anti-restriction endonuclease (Am), which is ...
Non-glucosylated (Glu-) T-even phage DNAs (hydroxymethylated DNAs) are restricted by E. coli RglA and RglB endonucleases with different specificities. RglB endonuclease is known to be strongly inhibited by anti-restriction endonuclease (Am), which is encoded by the bacteriophage T4 genome. In this study the am gene encoding anti-restriction endonuclease was cloned in a 0.8 kb EcoRl fragment from bacteriophage T4 genomic DNA. The location of the am gene was determined by subcloning to be on the 0.8 kb insert. Am activity from the cloned am gene was more prominent at 37℃ than 30℃ or 42℃. The 0.8 kb DNA fragment was transferred into T7 promoter vector pT7-6 to give rise to pARN100. The product of the am gene was overexpressed from pARN100, and its molecular weight was estimated to be 11,000 daltons.