How pathogenic bacteria evade mammalian sabotage in the battle for iron.
Many bacteria, including numerous human pathogens, synthesize small molecules known as siderophores to scavenge iron. Enterobactin, a siderophore produced by enteric bacteria, is surprisingly ineffective as an iron-scavenging agent for bacteria growing in animals because of its hydrophobicity and its sequestration by the mammalian protein siderocalin, a component of the innate immune system. However, pathogenic strains of Escherichia coli and Salmonella use enzymes encoded by the iroA gene cluster to tailor enterobactin by glycosylation and linearization. The resulting modified forms of enterobactin, known as salmochelins, can evade siderocalin and are less hydrophobic than enterobactin, restoring this siderophore's iron-scavenging ability in mammals.
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, USA.
Michael A
MA
Fischbach
Hening
H
Lin
David R
DR
Liu
Christopher T
CT
Walsh
D000818:Animals; D001419:Bacteria / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004758:Enterobactin / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D005960:Glucosides / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007501:Iron / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D012694:Serine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D017262:Siderophores / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism
D001426:Bacterial Proteins; D005960:Glucosides; D017262:Siderophores; D004758:Enterobactin; D012694:Serine; D007501:Iron