Nucleic Acids Research, 1988, Vol. 16, No. 14 6353-6360
© 1988
Articles |
Detection of an epitope, not required for polymerization, that is conserved between E.coli DNA polymerases I and III and bacteriophage T4 DNA polymerase
Department of Biochemistry, Biophysics and Genetics, University of Colorado Health Sciences Center Denver, CO 80262, USA
Received February 29, 1988.
Monoclonal antibodies directed against the
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.