Bacteria capture iron from heme by keeping tetrapyrrol skeleton intact.
Because heme is a major iron-containing molecule in vertebrates, the ability to use heme-bound iron is a determining factor in successful infection by bacterial pathogens. Until today, all known enzymes performing iron extraction from heme did so through the rupture of the tetrapyrrol skeleton. Here, we identified 2 Escherichia coli paralogs, YfeX and EfeB, without any previously known physiological functions. YfeX and EfeB promote iron extraction from heme preserving the tetrapyrrol ring intact. This novel enzymatic reaction corresponds to the deferrochelation of the heme. YfeX and EfeB are the sole proteins able to provide iron from exogenous heme sources to E. coli. YfeX is located in the cytoplasm. EfeB is periplasmic and enables iron extraction from heme in the periplasm and iron uptake in the absence of any heme permease. YfeX and EfeB are widespread and highly conserved in bacteria. We propose that their physiological function is to retrieve iron from heme.
Létoffé
Sylvie
S
Unité des Membranes Bactériennes, Département de Microbiologie, Institut Pasteur, CNRS URA 2172, 75724 Paris Cedex 15, France.
Heuck
Gesine
G
Delepelaire
Philippe
P
Lange
Norbert
N
Wandersman
Cécile
C
D027682:Cation Transport Proteins / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D006418:Heme / Q000737:chemistry*; D007501:Iron / Q000737:chemistry / Q000378:metabolism*; D033862:Iron-Binding Proteins / Q000378:metabolism*; D013058:Mass Spectrometry; D011485:Protein Binding; D011524:Protoporphyrins / Q000378:metabolism; D045725:Tetrapyrroles / Q000737:chemistry
D027682:Cation Transport Proteins; C543327:EfeB protein, E coli; D029968:Escherichia coli Proteins; D033862:Iron-Binding Proteins; D011524:Protoporphyrins; D045725:Tetrapyrroles; C543326:YfeX protein, E coli; D006418:Heme; C028025:protoporphyrin IX; D007501:Iron