大肠杆菌K-12 DNA甲基化酶活性的底物特异性研究。

Studies on the substrate specificity of the DNA methylase activity from Escherichia coli K-12.

作者信息

Schmidt A, Reinert H, Venner H, Bieber J

出版信息

Z Allg Mikrobiol. 1979;19(7):489-95. doi: 10.1002/jobm.3630190706.

DOI:10.1002/jobm.3630190706

Abstract

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) 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.

摘要

对来自大肠杆菌K-12的一种部分纯化的DNA甲基化酶提取物进行了检测，该提取物含有DNA腺嘌呤甲基化酶和DNA胞嘧啶甲基化酶活性，以不同的DNA种类作为底物。结果表明，所用DNA中6-甲基腺嘌呤（6-MAP）的天然含量会抑制DNA腺嘌呤甲基化酶的活性。另一方面，底物中已存在的5-甲基胞嘧啶（5-MC）并不影响DNA胞嘧啶甲基化酶的活性。以完全不含甲基化碱基的耐辐射微球菌的DNA作为对照。由于纺锤菌素优先结合DNA的富含AT的区域，因此研究了这种寡肽抗生素对DNA甲基化的影响。正如预期的那样，该抗生素主要抑制DNA的腺嘌呤甲基化。抑制程度取决于纺锤菌素与DNA磷酸的摩尔比。