MONOCLONAL-ANTIBODY NM11 RECOGNIZES A C-TERMINAL EPITOPE SHARED BY P300 AND CBP

The epitope recognized by the monoclonal antibody NM11, previously sho wn to recognize both CBP and p300, has been mapped here to the C-termi nal third of p300 and CBP by Western analysis of p300 and CBP prokaryo tic fusion proteins, More precise epitope mapping, carried out by scre ening a plasmid expression library derived from small randomly generat ed CBP cDNA fragments localizes the NM11 epitope to a 21 amino acid st retch spanning amino acids 2071-2091 near the CBP C-terminus. CBP and p300 differ by three noncontiguous residues within this 21 amino acid region, a difference that does not detectably affect the reactivity of NM11.