Identification of the E. coli groNB(nusB) gene product

The E. coli groNB(nusB) gene product has been previously shown to be necessary for bacteriophage lambda N protein function. The product of the groNB gene has been identified on SDS polyacrylamide gels after infection of UV-irradiated E. coli cells with various lambda groNB+ transducing phage derivatives. It is a polypeptide with an apparent molecular weight of 14,000 daltons. Transducing phage carrying either a deletion or an amber mutation in the groNB gene fail to synthesize the 14,000-Mr polypeptide chain upon infection of a sup+ host. However, am+ revertants of the lambda groNBam phage do induce the synthesis of the polypeptide.