title: A monoclonal antibody that recognizes the functional domain of Escherichia coli single-stranded DNA binding protein that includes the ssb-113 mutation.
abstract: We have isolated a monoclonal antibody against Escherichia coli single-stranded DNA binding protein (SSB) that recognizes the functional domain specified by the ssb-113 temperature-sensitive mutation, a domain which is distinct from the DNA-binding site. Although the ssb-113 and ssb-1 mutations result in many similar phenotypic defects, they differ significantly in others, indicating that they affect different functional domains of the protein. Whereas the SSB-1 mutant protein is clearly defective in tetramer formation and is also unable to bind single-stranded DNA at nonpermissive temperatures, no similar in vitro defects have yet been found in the SSB-113 mutant protein. In fact, the only reported in vitro effect of the ssb-113 mutation on the protein is a slight increase in its helix destabilizing ability. Competition radioimmunoassays using a monoclonal antibody demonstrated that SSB-113 mutant protein, containing a single amino acid substitution at position 176 (the penultimate residue), did not compete with SSB while SSB-1 protein (with a single change at position 55) did compete with SSB. This analysis was refined by studies with a proteolysis fragment and with peptides derived from both SSB and SSB-113. The results indicate that the antibody recognizes a determinant near the COOH-terminal end of the protein and that the SSB-113 mutation lies within or very close to this determinant.
authors.forename: J W
authors.initials: JW
authors.lastname: Chase
authors.forename: J
authors.initials: J
authors.lastname: Flory
authors.forename: N H
authors.initials: NH
authors.lastname: Ruddle
authors.forename: J B
authors.initials: JB
authors.lastname: Murphy
authors.forename: K R
authors.initials: KR
authors.lastname: Williams
mesh_terms: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D001667:Binding, Competitive; D003488:Cyanogen Bromide; D004268:DNA-Binding Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D000939:Epitopes / Q000032:analysis*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D009154:Mutation; D010446:Peptide Fragments / Q000032:analysis; D011863:Radioimmunoassay
chemical_list: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D004268:DNA-Binding Proteins; D000939:Epitopes; D010446:Peptide Fragments; D003488:Cyanogen Bromide