Physical and genetic characterization of cloned enterobactin genomic sequences from Escherichia coli K-12

Abstract

We have cloned genes responsible for enterobactin synthesis ( entD) and transport ( fepA,fes) from Escherichia coli K-12. Revelant recombinant plasmids enabled EntD − and transport-defective mutants to grow on iron-limiting medium. Subcloning and deletion analysis demonstrated that the gene order is entD-fepA-fes. Protein synthesis studies in minicells suggest that FepA is first translated as an M r 84000 precursor, which is subsequently cleaved to the active M r 81000 receptor; the fes gene product is an M r 44000 protein; no polypeptide has been identified as the entD gene product.