The nucleotide sequence of the Escherichia coli K12 nusB (groNB) gene

The nusB (groNB) gene product of Escherichia coli plays a pivotal role in allowing bacteriophage lambda N protein to function as an antiterminator of mRNA transcription and in modulating host gene expression. In addition it is essential for bacterial viability since mutations in it result in a cold-sensitivity phenotype for growth. We have previously cloned the nusB gene and shown it to code for a 14,500-Mr protein. Here we present the primary DNA sequence of the nusB gene. From the sequence we deduce that it codes for a slightly basic protein (21 basic as opposed to 20 acidic amino acids) composed of 139 amino acids with a cumulative 15,689-Mr. The predicted N-terminal amino acid sequence as well as the overall amino acid composition agrees well with that of the purified protein.