The fhu genes of Rhizobium leguminosarum, specifying siderophore uptake proteins: fhuDCB are adjacent to a pseudogene version of fhuA.
A mutant of Rhizobium leguminosarum was isolated which fails to take up the siderophore vicibactin. The mutation is in a homologue of fhuB, which in Escherichia coli specifies an inner-membrane protein of the ferric hydroxamate uptake system. In Rhizobium, fhuB is in an operon fhuDCB, which specifies the cytoplasmic membrane and periplasmic proteins involved in siderophore uptake. fhuDCB mutants make vicibactin when grown in Fe concentrations that inhibit its production in the wild-type. Nodules on peas induced by fhuDCB mutants were apparently normal in N2 fixation. Transcription of an fhuDCB-lacZ fusion was Fe-regulated, being approximately 10-fold higher in Fe-depleted cells. Downstream of fhuB, in the opposite orientation, is a version of fhuA whose homologues in other bacteria specify hydroxamate outer-membrane receptors. This fhuA gene appears to be a pseudogene with stop codons and undetectable expression.
Stevens
James B
JB
School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
Carter
Robert A
RA
School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
Hussain
Haitham
H
School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
Carson
Kerry C
KC
Centre for Rhizobium Studies, School of Biological Sciences and Biotechnology, Division of Science, Murdoch University, Murdoch, Western Australia 6150, Australia.
Dilworth
Michael J
MJ
Centre for Rhizobium Studies, School of Biological Sciences and Biotechnology, Division of Science, Murdoch University, Murdoch, Western Australia 6150, Australia.
Johnston
Andrew W B
AWB
School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
D018528:ATP-Binding Cassette Transporters; D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics*; D029968:Escherichia coli Proteins; D015870:Gene Expression; D005798:Genes, Bacterial; D007501:Iron / Q000032:analysis; D008565:Membrane Proteins / Q000235:genetics; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation / Q000235:genetics; D010456:Peptides, Cyclic / Q000096:biosynthesis; D033902:Periplasmic Binding Proteins; D011544:Pseudogenes; D011991:Receptors, Virus / Q000235:genetics; D016961:Rhizobium leguminosarum / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D017262:Siderophores / Q000378:metabolism*; D013559:Symbiosis / Q000235:genetics; D014157:Transcription Factors / Q000096:biosynthesis
D018528:ATP-Binding Cassette Transporters; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C104568:FeuQ protein, bacteria; C050900:FhuA protein, E coli; C066629:FhuC protein, E coli; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D010456:Peptides, Cyclic; D033902:Periplasmic Binding Proteins; D011991:Receptors, Virus; D017262:Siderophores; D014157:Transcription Factors; C119259:vicibactin; C069968:fhuB protein, E coli; C069969:fhuD protein, E coli; D007501:Iron