Cloning, sequencing, and characterization of the Azospirillum brasilense fhuE gene.
The fhuE gene of Escherichia coli encodes the FhuE protein, which is a receptor protein in the coprogen-mediated siderophore iron-transport system. A fhuE gene homologue from Azospirillum brasilense, a nitrogen-fixing soil bacterium that lives in association with the roots of cereal grasses, was cloned, sequenced, and characterized. The A. brasilense fhuE encodes a protein of 802 amino acids with a predicted molecular weight of approximately 87 kDa. The deduced amino-acid sequence showed a high level of homology to the sequences of all the known fhuE gene products. The fhuE mutant was sensitive to iron starvation and defective in coprogen-mediated iron uptake. The mutant failed to express one membrane protein of approximately 78 kDa that was induced by iron starvation in the wild type. Complementation studies showed that the A. brasilense fhuE gene, when present on a low-copy number plasmid, could restore the functions of the mutant. Mutation in fhuE gene did not affect nitrogen fixation.
Cui
Yanhua
Y
National Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, 100094, PRC.
Tu
Ran
R
Guan
Yue
Y
Ma
Luyan
L
Chen
Sanfeng
S
D000595:Amino Acid Sequence; D015806:Azospirillum brasilense / Q000235:genetics* / Q000378:metabolism; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001483:Base Sequence; D001692:Biological Transport / Q000235:genetics; D003001:Cloning, Molecular; D005798:Genes, Bacterial; D006877:Hydroxamic Acids / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics*; D017421:Sequence Analysis; D017262:Siderophores / Q000378:metabolism
D001425:Bacterial Outer Membrane Proteins; D006877:Hydroxamic Acids; D011956:Receptors, Cell Surface; D017262:Siderophores; C010896:coprogen; D007501:Iron