NDD, THE BACTERIOPHAGE-T4 PROTEIN THAT DISRUPTS THE ESCHERICHIA-COLI NUCLEOID, HAS A DNA-BINDING ACTIVITY

Early in a bacteriophage T4 infection, the phage ndd gene causes the r apid destruction of the structure of the Escherichia coli nucleoid. Ev en at very low levels, the Ndd protein is extremely toxic to cells. In uninfected E. coli, overexpression of the cloned ndd gene induces dis ruption of the nucleoid that is indistinguishable from that observed a fter T4 infection. A preliminary characterization of this protein indi cates that it has a double-stranded DNA binding activity with a prefer ence for bacterial DNA rather than phage T4 DNA. The targets of Ndd ac tion may be the chromosomal sequences that determine the structure of the nucleoid.