title: N-terminal DNA-binding domains contribute to differential DNA-binding specificities of NF-kappa B p50 and p65.
abstract: We previously reported that either oxidation or alkylation of NF-kappa B in vitro abrogates DNA binding. We used this phenomenon to help elucidate structural determinants of NF-kappa B binding. We now demonstrate that Cys-62 of NF-kappa B p50 mediates the redox effect and lies within an N-terminal region required for DNA binding but not for dimerization. Several point mutations in this region confer a transdominant negative binding phenotype to p50. The region is highly conserved in all Rel family proteins, and we have determined that it is also critical for DNA binding of NF-kappa B p65. Replacement of the N-terminal region of p65 with the corresponding region from p50 changes its DNA-binding specificity towards that of p50. These data suggest that the N-terminal regions of p50 and p65 are critical for DNA binding and help determine the DNA-binding specificities of p50 and p65. We have defined within the N-terminal region a sequence motif, R(F/G)(R/K)YXCE, which is present in Rel family proteins and also in zinc finger proteins capable of binding to kappa B sites. The potential significance of this finding is discussed.
authors.affiliation: Section on Pulmonary and Molecular Immunology, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892.
authors.forename: M B
authors.initials: MB
authors.lastname: Toledano
authors.forename: D
authors.initials: D
authors.lastname: Ghosh
authors.forename: F
authors.initials: F
authors.lastname: Trinh
authors.forename: W J
authors.initials: WJ
authors.lastname: Leonard
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D003545:Cysteine / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D016328:NF-kappa B / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D017386:Sequence Homology, Amino Acid
chemical_list: D016328:NF-kappa B; D004247:DNA; D003545:Cysteine