title: Histidine-15: an important role in the cytotoxic activity of human tumor necrosis factor.
abstract: The amino acids that are required for the cytotoxic activity of recombinant human tumor necrosis factor-alpha (TNF) were investigated by chemical modification and oligonucleotide-directed site-specific mutagenesis. TNF contains three histidine residues, located at positions 15, 73 and 78. The histidine-specific reagent diethylpyrocarbonate (DEP) was used to chemically modify TNF. The chemical inactivation of the in vitro cytotoxic activity of this lymphokine (using murine L929 target cells) was found to be time- and dose-dependent. Inactivated TNF failed to compete with fully bioactive [125I]TNF for human MCF-7 target cell receptors. Mutant polypeptides of TNF were genetically engineered by oligonucoleotide-directed site-specific mutagenesis. The cytotoxicity of a double histidine mutant, in which histidine-73 and histidine-78 were replaced with glutamine, was not altered and was chemically inactivated by DEP. Substituting glutamine for histidine-15 resulted in 10-15% of the wild-type bioactivity. Replacing histidine-15 with either asparagine, lysine or glycine resulted in a biologically inactive molecule. The data show that the histidine residue at position 15 is an amino acid that is required for the cytotoxic activity of TNF.
authors.affiliation: Department of Protein Chemistry, Cetus Corporation, Emeryville, CA 94608.
authors.forename: R
authors.initials: R
authors.lastname: Yamamoto
authors.forename: A
authors.initials: A
authors.lastname: Wang
authors.forename: C R
authors.initials: CR
authors.lastname: Vitt
authors.forename: L S
authors.initials: LS
authors.lastname: Lin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000970:Antineoplastic Agents; D001667:Binding, Competitive; D002460:Cell Line; D003001:Cloning, Molecular; D004247:DNA / Q000187:drug effects* / Q000235:genetics; D004047:Diethyl Pyrocarbonate; D006639:Histidine / Q000502:physiology*; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D011956:Receptors, Cell Surface / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor; D013329:Structure-Activity Relationship; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics* / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D011956:Receptors, Cell Surface; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D006639:Histidine; D004247:DNA; D004047:Diethyl Pyrocarbonate