Detection of an epitope, not required for polymerization, that is conserved between E.coli DNA polymerases I and III and bacteriophage T4 DNA polymerase.
Monoclonal antibodies directed against the alpha subunit of the DNA polymerase III holoenzyme (1) of E. coli were tested for cross-reactivity with a variety of polymerases. We found that one monoclonal antibody bound to E. coli DNA polymerase I as well as to DNA polymerase III. A weaker, but specific, interaction was also detected with T4 DNA polymerase. We exploited the proteolysis procedure developed by Setlow, Brutlag and Kornberg (2) to determine which domain of DNA polymerase I contained the conserved epitope. Contrary to expectations, it was not found in the polymerase domain, but in the 5'----3' exonuclease domain. This reveals a sequence or structure, sufficiently important to be conserved among these polymerases, that is not directly involved in the polymerization reaction.
Franden
M A
MA
Department of Biochemistry and Genetics, University of Colorado Health Sciences Center, Denver 80262.
McHenry
C S
CS
D000911:Antibodies, Monoclonal / Q000276:immunology; D003429:Cross Reactions; D004247:DNA / Q000096:biosynthesis; D004256:DNA Polymerase I / Q000276:immunology*; D004258:DNA Polymerase III / Q000276:immunology*; D004259:DNA-Directed DNA Polymerase / Q000276:immunology*; D000939:Epitopes; D007163:Immunosorbent Techniques; D013604:T-Phages / Q000201:enzymology
D000911:Antibodies, Monoclonal; D000939:Epitopes; D004247:DNA; D004256:DNA Polymerase I; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase