Four monoclonal antibodies (MAbs) recognizing HIV-1 reverse transcriptase (RT) were shown here to cross-react with the β′ subunit of Escherichia coli RNA polymerase (RNAP). The anti-RT MAbs bind to a peptide comprising residues 294–305 of the RT amino acid sequence. Computer analyses revealed sequence similarity between this peptide and two regions of the RNAP β′ subunit. MAb-binding studies using RT mutants suggested that the epitope is located to amino acids 652–663 of the β′ sequence. One of the MAbs which inhibited the polymerase activity of RT also mediated a dose dependent inhibition of the RNAP activity.
