Extent of equilibrium perturbation of the DNA helix upon enzymatic methylation of adenine residues.

Journal Article (Journal Article)

The extent of equilibrium perturbation of the DNA helix associated with enzymatic methylation of dA residues has been determined by the agarose gel electrophoresis band-shift method. Utilization of EcoRI methylase under conditions of reduced specificity together with Escherichia coli dam methylase permitted modification of up to 300 dA residues/plasmid pBR322 dimer. A conformational change associated with methylation was observed, with the magnitude of the transition being linear with extent of modification of relaxed DNA circles. The conformational change corresponds to an unwinding of the DNA helix by 0.5 degrees/methyl group transferred to relaxed molecules. The magnitude of the effect was independent of temperature from 5-37 degrees C indicating that it is not the consequence of a thermal transition within this range.

Full Text

Duke Authors

Cited Authors

  • Cheng, SC; Herman, G; Modrich, P

Published Date

  • January 10, 1985

Published In

Volume / Issue

  • 260 / 1

Start / End Page

  • 191 - 194

PubMed ID

  • 3880739

International Standard Serial Number (ISSN)

  • 0021-9258


  • eng

Conference Location

  • United States