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Studies on the substrate specificity of the DNA methylase activity from Escherichia coli K‐12
Author(s) -
Schmidt A.,
Reinert H.,
Venner H.,
Bieber J.
Publication year - 1979
Publication title -
zeitschrift für allgemeine mikrobiologie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0044-2208
DOI - 10.1002/jobm.19790190706
Subject(s) - cytosine , dna , netropsin , biochemistry , escherichia coli , circular bacterial chromosome , dna methylation , biology , microbiology and biotechnology , chemistry , dna polymerase , gene , gene expression , minor groove
A partially purified extract of DNA methylases from E. coli K‐12 containing DNA‐adenine as well as DNA‐cytosine methylase activities has been examined with respect to different DNA species as substrates. The results show that the natural content of 6‐MAP 1 ) in the applied DNA represses the DNA‐adenine methylase activity. On the other hand, 5‐MC, already present in the substrate does not influence the activity of the DNA‐cytosine methylase. DNA from Micrococcus radiodurans , which is completely free of methylated bases served as comparison. Since netropsin preferentially binds to AT‐rich regions of DNA, the influence of this oligopeptide antibiotic on the methylation of DNA was investigated. As expected the antibiotic predominantly inhibits adenine methylation of DNA. The degree of inhibition depends on the molar ratio of netropsin to DNA phosphate.