ISOLATION AND CHARACTERIZATION OF THE HAEMOPHILUS-INFLUENZAE TOLQ, TOLR, TOLA AND TOLB GENES

The tolQ, R, A and B genes have been isolated from the DNA of Haemophi lus influenzae and sequenced. The deduced amino acid (aa) sequence of the H. influenzae TolQ, TolR, TolA and TolB show 67, 63, 41 and 62% id entity with Escherichia coli TolQRAB proteins, respectively. These fou r proteins are involved in transport of colicins and phages across the cell envelope. The translational stop codon of TolB (the last gene in the cluster) is 23 bases upstream of the start codon of the P6 lipopr otein gene. Primer extension and Northern blot analysis revealed that the start of the P6 transcript is within the tolB gene. Nucleotide seq uence (nt) analysis of the entire tolQRABP6 region shows a transcripti onal terminator immediately downstream of the P6 gene. The tolQRABP6 g ene cluster of H. influenzae may thus constitute an operon.