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PubMed · 1069283

Colicin E2 is DNA endonuclease.

K Schaller·M Nomura
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Abstract

Colicin E2 purified by conventional methods contains a tightly bound low-molecular-weight protein, as has been found with purified colicin E3 [Jakes,N.&Zinder,N.D.(1974) Proc. Natl. Acad. Sci. USA 71, 3380-3384]. Such E2 preparations do not cause DNA cleavage in vitro. After separation from the low-molecular-weight protein, colicin E2 retained the original in vivo killing activity, and in addition showed a high activity in vitro in cleaving various DNA molecules, such as a ColE1 hybrid plasmid and DNAs from Escherichia coli, lambda phage, chiX174 phage, and simian virus 40. The low-molecular-weight protein ("E2-immunity protein") specifically prevented this in vitro DNA cleavage reaction, i.e., had an "immunity function." The results demonstrate that colicin E2 itself is a DNA endonuclease and explain the in vivo effects caused by E2 in sensitive cells as well as the mechanism of immunity in E2-colicinogenic cells.

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ColicinsDNADNA, BacterialDNA, CircularEndonucleasesGuanidinesMolecular WeightJournal ArticleResearch Support, U.S. Gov't, Non-P.H.S.Research Support, U.S. Gov't, P.H.S.

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K Schaller, M Nomura. 1976. Colicin E2 is DNA endonuclease.. https://doi.org/10.1073/pnas.73.11.3989

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