Open AccessCleavage of Bacteriophage f1 DNA by the Restriction Enzyme of Escherichia coli B
Author(s) -
Kensuke Horiuchi,
Norton D. Zinder
Publication year - 1972
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.69.11.3220
Subject(s) - restriction enzyme , endonuclease , cleavage (geology) , dna , microbiology and biotechnology , escherichia coli , bacteriophage , biology , mutant , denaturation (fissile materials) , enzyme , ecori , chemistry , biochemistry , gene , paleontology , fracture (geology) , nuclear chemistry
We studied the cleavage of the replicative-form DNA (RF I) of bacteriophage f1 and its SB mutants by purified restriction endonuclease ofE. coli B. The results indicate that: (i ) Circular replicative forms are broken once to yield full-length linear molecules (RF III). Such linear molecules are less susceptible than RF I to endonuclease R-B. (ii ) The genetic sites (SB sites) that confer on the DNA susceptibility to B-restriction are not the actual sites of cleavage. The number of possible cleavage sites is larger than the number of SB sites. We conclude this because an RF III molecule produced by endonuclease R-B from RF I of a mutant that has only one SB site can be circularized by denaturation and renaturation. (iii ) The SB site is not modified when the DNA is cleaved, since an SB site can be used repeatedly by endonuclease R-B; the RF III described inii can be cleaved by the same enzyme after denaturation and renaturation.