The colicin G, H and X determinants encode microcins M and H47, which might utilize the catecholate siderophore receptors FepA, Cir, Fiu and IroN.
The colicin G producer Escherichia coli CA46, the colicin H producer E. coli CA58 and E. coli Nissle 1917 (DSM 6601) were shown to produce microcin H47 and the newly described microcin M. Both microcins were exported like colicin V by an RND-type export system, including TolC. The gene cluster encoding microcins H47 and M in strains CA46 and CA58 is nearly identical to that in strain DSM 6601, except that two additional genes are included. A Fur box identified in front of the microcin-encoding genes explained the observed iron regulation of microcin production. The catecholate siderophore receptors Fiu, Cir and FepA from E. coli and IroN, Cir and FepA from Salmonella were identified as receptors for microcins M, H47 and E492. IroN takes up the glucose-containing catecholate siderophore salmochelin, whose synthesis is encoded in the iro gene cluster found in Salmonella and certain, often uropathogenic, E. coli strains. A gene in this iro cluster, iroB, which encodes a putative glycosyltransferase, was also found in the microcin H47/M and microcin E492 gene clusters. These microcins could aid the producing strain in competing against enterobacteria that utilize catecholate siderophores.
Patzer
S I
SI
Mikrobiologie/Membranphysiologie, Universität Tübingen, Auf der Morgenstelle 28, Tübingen, Germany.
Baquero
M R
MR
Unidad de Genetica Molecular, Hospital Ramon y Cajal, Madrid, Spain.
Bravo
D
D
Unidad de Genetica Molecular, Hospital Ramon y Cajal, Madrid, Spain.
Moreno
F
F
Unidad de Genetica Molecular, Hospital Ramon y Cajal, Madrid, Spain.
Hantke
K
K
Mikrobiologie/Membranphysiologie, Universität Tübingen, Auf der Morgenstelle 28, Tübingen, Germany.
D023181:Antimicrobial Cationic Peptides; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003087:Colicins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D005810:Multigene Family; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*
D023181:Antimicrobial Cationic Peptides; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D003087:Colicins; D010455:Peptides; D011956:Receptors, Cell Surface; C029489:enterobactin receptor; C444452:microcin H47; C035902:siderophore receptors