Recognition sequence of the dam methylase of Escherichia coli K12 and mode of cleavage of Dpn I endonuclease.

Journal Article (Journal Article)

The recognition sequence for the dam methylase of Escherichia coli K12 has been determined directly by use of in vivo methylated ColE1 DNA or DNA methylated in vitro with purified enzyme. The methylase recognizes the symmetric tetranucleotide d(pG-A-T-C) and introduces two methyl groups per site in duplex DNA with the product of methylation being 6-methylaminopurine. This work has also demonstrated that Dpn I restriction endonuclease cleaves on the 3' side of the modified adenine within the methylated sequence to yield DNA fragments possessing fully base-paired termini. All sequences in ColE1 DNA methylated by the dam enzyme are subject to double strand cleavage by Dpn I endonuclease. Therefore, this restriction enzyme can be employed for mapping the location of sequences possessing the dam modification.

Full Text

Duke Authors

Cited Authors

  • Geier, GE; Modrich, P

Published Date

  • February 25, 1979

Published In

Volume / Issue

  • 254 / 4

Start / End Page

  • 1408 - 1413

PubMed ID

  • 368070

International Standard Serial Number (ISSN)

  • 0021-9258


  • eng

Conference Location

  • United States