Identification of a new gene (secA) and gene product involved in the secretion of envelope proteins in Escherichia coli

We have constructed lambda specialized transducing phages which carry an Escherichia coli gene (secA) involved in the secretion of certain envelope proteins. These phage have been used to show that secA is a new gene to the clockwise side of envA. The secA mutation previously described, secA5l(Ts) (D. B. Oliver and J. Beckwith, Cell 25:765-772, 1981), is recessive to the wild-type allele. We have also isolated Tn5 insertions in the gene carried on the transducing phage to further define the gene. These phage were used to infect UV-irradiated cells to allow the identification of the secA gene product as a 92-kilodalton polypeptide and to show that transcription of secA is clockwise relative to the E. coli genetic map.