Functional Differences between Heme Permeases: Serratia marcescens HemTUV Permease Exhibits a Narrower Substrate Specificity (Restricted to Heme) Than the Escherichia coli DppABCDF Peptide-Heme Permease

Serratia marcescens hemTUV genes encoding a potential heme permease were cloned in Escherichia coli recombinant mutant FB827 dppF ::Km(pAM 238-hasR). This strain, which expresses HasR, a foreign heme outer membrane receptor, is potentially capable of using heme as an iron source. However, this process is invalidated due to a dppF ::Km mutation which inactivates the Dpp heme/peptide permease responsible for heme, dipeptide, and δ-aminolevulinic...