Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

With the use of the strain-overproducer restriction endonuclease R.EcoRV was isolated and purified to homogeneity. The molecular mass of the enzyme was determined by gel filtration and polyacrylamide gel electrophoresis to be 25 000 daltons. According to the data of immunological tests R.EcoRV differs in its antigenic characteristics from restriction endonucleases R.EcoRI and R.EcoRII. Dependence of enzyme activity on pH, ionic strength, temperature, presence of divalent cations (Mn2+, Mg2+, Co2+, Zn2+, Ni2+ and Cd2+) and organic solvents (glycerol, dimethylsulfoxide, ethanol) has been studied. It was shown that under conditions of replacement of Mg2+ for Mn2+ or after addition of organic solvents relaxation of R.EcoRV specificity takes place. It was shown also that R.EcoRV is able to digest T-even bacteriophage DNAs with different types and extents of modification. DNA modified by the action of MR.EcoRV system in vivo is susceptible to R.EcoRV in vitro. Under conditions of relaxed specificity noncanonical sites are susceptible to R.EcoRV attack. The fragments resulted may be cloned in canonical pBR322 EcoRV site.
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PMID:[EcoRV restrictase: physical and catalytic properties of homogenous enzyme]. 620 Jul 65

The recombination properties of Escherichia coli strains expressing the red genes of bacteriophage lambda and lacking recBCD function either by mutation or by expression of lambda gam were examined. The substrates for recombination were nonreplicating lambda chromosomes, introduced by infection; Red-mediated recombination was initiated by a double-strand break created by the action of a restriction endonuclease in the infected cell. In one type of experiment, two phages marked with restriction site polymorphisms were crossed. Efficient formation of recombinant DNA molecules was observed in ruvC+ recG+, ruvC recG+, ruvC+ recG, and ruvC recG hosts. In a second type of experiment, a 1-kb nonhomology was inserted between the double-strand break and the donor chromosome's restriction site marker. In this case, recombinant formation was found to be partially dependent upon ruvC function, especially in a recG mutant background. In a third type of experiment, the recombining partners were the host cell chromosome and a 4-kb linear DNA fragment containing the cat gene, with flanking lac sequences, released from the infecting phage chromosome by restriction enzyme cleavage in the cell; the formation of chloramphenicol-resistant bacterial progeny was measured. Dependence on RuvC varied considerably among the three types of cross. However, in all cases, the frequency of Red-mediated recombination was higher in recG than in recG+. These observations favor models in which RecG tends to push invading 3'-ended strands back out of recombination intermediates.
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PMID:Roles of RuvC and RecG in phage lambda red-mediated recombination. 1046 13