Genetics of the iron dicitrate transport system of Escherichia coli.

摘要: Escherichia coli B and K-12 express a citrate-dependent iron(III) transport system for which three structural genes their arrangement products have been determined. The fecA gene of E. consists 2,322 nucleotides encodes polypeptide containing signal sequence 33 amino acids. cleavage site was determined by acid analysis the unprocessed protein mature protein. For processed form length 741 acids calculated. FecA in outer membrane contains at N terminus "TonB box," pentapeptide, has hitherto found all receptors colicins functionally require TonB In addition, dyad repeat GAAAATAATTCTTATTTCG is proposed to serve as binding Fur iron repressor fecB mapped downstream with an apparent molecular weight 30,000. It synthesized precursor, periplasm. fecD follows related membrane-bound 28,000. Mu d1 insertion mutants upstream fecA, fec were not inducible limitation citrate, indicating regulatory region, termed fecI, controls expression.