Emilie Verplaetse, Gwenaëlle André-Leroux, Philippe Duhutrel, Gwendoline Coeuret, Stéphane Chaillou, Christina Nielsen-Leroux, Marie-Christine Champomier-Vergès
is a nonpathogenic lactic acid bacterium and a natural inhabitant of meat ecosystems. Although red meat is a heme-rich environment, does not need iron or heme for growth, although it possesses a heme-dependent catalase. Iron incorporation into from myoglobin and hemoglobin was previously shown by microscopy and the genome reveals the complete equipment for iron and heme transport. Here, we report the characterization of a five-gene cluster (from to []) encoding a putative metal iron ABC transporter. Interestingly, this cluster, together with a heme-dependent catalase gene, is also conserved in other species from the meat ecosystem. Our bioinformatic analyses revealed that the locus might correspond to a complete machinery of an energy coupling factor (ECF) transport system. We quantified the intracellular heme in the wild type (WT) and in our Δ deletion mutant using an intracellular heme sensor and inductively coupled plasma mass spectrometry for quantifying incorporated Fe heme. We showed that in the WT , heme accumulation occurs rapidly and massively in the presence of hemin, while the deletion mutant was impaired in heme uptake; this ability was restored by in complementation. Our results establish the main role of the Lsa1836-1840 ECF-like system in heme uptake. Therefore, this research outcome sheds new light on other possible functions of ECF-like systems. is a nonpathogenic bacterial species exhibiting high fitness in heme-rich environments such as meat products, although it does not need iron or heme for growth. Heme capture and utilization capacities are often associated with pathogenic species and are considered virulence-associated factors in the infected hosts. For these reasons, iron acquisition systems have been deeply studied in such species, while for nonpathogenic bacteria the information is scarce. Genomic data revealed that several putative iron transporters are present in the genome of the lactic acid bacterium In this study, we demonstrate that one of them is an ECF-like ABC transporter with a functional role in heme transport. Such evidence has not yet been brought for an ECF; therefore, our study reveals a new class of heme transport system.
