Alteration of NF-kappa B p50 DNA binding kinetics by S-nitrosylation

Biochem Biophys Res Commun. 1997 Sep 29;238(3):703-6. doi: 10.1006/bbrc.1997.7279.


Nitric oxide (NO) regulates a wide variety of cellular functions, in part, by formation of S-NO bonds at critical active site thiol groups within proteins, including transcription factors. Previous studies have qualitatively demonstrated that S-nitrosothiol formation can alter transcription factor binding to the DNA recognition site. To more precisely define the effect of S-nitrosylation on transcription factor binding, the equilibrium binding constant was derived for S-nitrosylated NF-kappa B p50 (S-NO-p50) in a cell free system utilizing gel shift assays. Binding of NF-kappa B p50 subjected to the nitrosylation conditions in the absence of NaNO2 (C-p50-2) was not different from that of wild type NF-kappa B (C-p50-1). The extent of S-NO-p50 binding to its DNA target sequence was significantly decreased in comparison to that noted with C-p50-1 and C-p50-2. The binding constant was derived for each of the NF-kappa B variants: C-p50-1 = 1.01 x 10(10) M(-1); C-p50-2 = 0.92 x 10(10) M(-1); and S-NO-p50 = 0.28 x 10(10) M(-1). These data indicate that S-nitrosylation of p50 decreases its affinity for the target DNA sequence by four-fold.

MeSH terms

  • Binding Sites / genetics
  • DNA / metabolism*
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / metabolism
  • DNA-Binding Proteins / physiology
  • Electrophoresis, Polyacrylamide Gel
  • Humans
  • NF-kappa B / chemistry
  • NF-kappa B / metabolism*
  • NF-kappa B / physiology
  • NF-kappa B p50 Subunit
  • Nitric Oxide / metabolism*
  • Nitric Oxide / physiology


  • DNA-Binding Proteins
  • NF-kappa B
  • NF-kappa B p50 Subunit
  • Nitric Oxide
  • DNA