The salt dependence of the interferon regulatory factor 1 DNA binding domain binding to DNA reveals ions are localized around protein and DNA.

ABSTRACT: The equilibrium dissociation constant of the DNA binding domain of interferon regulatory factor 1 (IRF1 DBD) for its DNA binding site depends strongly on salt concentration and salt type. These dependencies are consistent with IRF1 DBD binding to DNA, resulting in the release of cations from the DNA and both release of anions from the protein and uptake of a cation by the protein. We demonstrated this by utilizing the fact that the release of fluoride from protein upon complex formation does not contribute to the salt concentration dependence of binding and by studying mutants in which charged residues in IRF1 DBD that form salt bridges with DNA phosphates are changed to alanine. The salt concentration dependencies of the dissociation constants of wild-type IRF1 DBD and the mutants R64A, D

SUBMITTER: Hargreaves VV 

PROVIDER: S-EPMC2824552 | biostudies-literature | 2008 Apr

REPOSITORIES: biostudies-literature