1887

Abstract

has multiple systems for iron acquisition, including the use of haem as an iron source. Haem internalization involves the ShmR haem outer membrane receptor and the locus, which participates in haem transport across the cytoplasmic membrane. Previous studies have demonstrated that expression of the gene is negatively regulated by iron through RirA. Here, we identify in a genetic screen for mutants that displayed aberrant control of . The normal induction of in response to iron limitation was lost in the mutant, showing that this gene positively affects expression. Moreover, the HmuP protein is not part of the haemin transporter system. Analysis of gene expression and siderophore production indicates that disruption of does not affect other genes related to the iron-restriction response. Our results strongly indicate that the main function of HmuP is the transcriptional regulation of . Sequence alignment of HmuP homologues and comparison with the NMR structure of CGA009 HmuP protein revealed that certain amino acids localized within predicted -sheets are well conserved. Our data indicate that at least one of the -sheets is important for HmuP activity.

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2010-06-01
2024-10-14
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References

  1. Allaway D., Schofield N. A., Leonard M. E., Gilardoni L., Finan T. M., Poole P. S. 2001; Use of differential fluorescence induction and optical trapping to isolate environmentally induced genes. Environ Microbiol 3:397–406
    [Google Scholar]
  2. Amarelle V., O'Brian M. R., Fabiano E. 2008; ShmR is essential for utilization of heme as a nutritional iron source in Sinorhizobium meliloti. Appl Environ Microbiol 74:6473–6475
    [Google Scholar]
  3. Andrews S. C., Robinson A. K., Rodriguez-Quinones F. 2003; Bacterial iron homeostasis. FEMS Microbiol Rev 27:215–237
    [Google Scholar]
  4. Arnold K., Bordoli L., Kopp J., Schwede T. 2006; The SWISS-MODEL workspace: a web-based environment for protein structure homology modelling. Bioinformatics 22:195–201
    [Google Scholar]
  5. Beringer J. E. 1974; R factor transfer in Rhizobium leguminosarum. J Gen Microbiol 84:188–198
    [Google Scholar]
  6. Chao T. C., Becker A., Buhrmester J., Puhler A., Weidner S. 2004; The Sinorhizobium meliloti fur gene regulates, with dependence on Mn(II), transcription of the sitABCD operon, encoding a metal-type transporter. J Bacteriol 186:3609–3620
    [Google Scholar]
  7. Chao T. C., Buhrmester J., Hansmeier N., Puhler A., Weidner S. 2005; Role of the regulatory gene rirA in the transcriptional response of Sinorhizobium meliloti to iron limitation. Appl Environ Microbiol 71:5969–5982
    [Google Scholar]
  8. Cuiv P. O., Clarke P., Lynch D., O'Connell M. 2004; Identification of rhtX and fptX, novel genes encoding proteins that show homology and function in the utilization of the siderophores rhizobactin 1021 by Sinorhizobium meliloti and pyochelin by Pseudomonas aeruginosa, respectively. J Bacteriol 186:2996–3005
    [Google Scholar]
  9. Cuiv P. O., Keogh D., Clarke P., O'Connell M. 2008; The hmuUV genes of Sinorhizobium meliloti 2011 encode the permease and ATPase components of an ABC transport system for the utilization of both haem and the hydroxamate siderophores, ferrichrome and ferrioxamine B. Mol Microbiol 70:1261–1273
    [Google Scholar]
  10. Diaz-Mireles E., Wexler M., Sawers G., Bellini D., Todd J. D., Johnston A. W. 2004; The Fur-like protein Mur of Rhizobium leguminosarum is a Mn2+-responsive transcriptional regulator. Microbiology 150:1447–1456
    [Google Scholar]
  11. Ditta G., Stanfield S., Corbin D., Helinski D. R. 1980; Broad host range DNA cloning system for Gram-negative bacteria: construction of a gene bank of Rhizobium meliloti. Proc Natl Acad Sci U S A 77:7347–7351
    [Google Scholar]
  12. Finan T. M., Hartweig E., LeMieux K., Bergman K., Walker G. C., Signer E. R. 1984; General transduction in Rhizobium meliloti. J Bacteriol 159:120–124
    [Google Scholar]
  13. Georgiadis M. M., Komiya H., Chakrabarti P., Woo D., Kornuc J. J., Rees D. C. 1992; Crystallographic structure of the nitrogenase iron protein from Azotobacter vinelandii. Science 257:1653–1659
    [Google Scholar]
  14. Griffitts J. S., Long S. R. 2008; A symbiotic mutant of Sinorhizobium meliloti reveals a novel genetic pathway involving succinoglycan biosynthetic functions. Mol Microbiol 67:1292–1306
    [Google Scholar]
  15. Guex N., Peitsch M. C. 1997; SWISS-MODEL and the Swiss-PdbViewer: an environment for comparative protein modeling. Electrophoresis 18:2714–2723
    [Google Scholar]
  16. Hanahan D. 1983; Studies on transformation of Escherichia coli with plasmids. J Mol Biol 166:557–580
    [Google Scholar]
  17. Hennecke H. 1992 The Role of Respiration in Symbiotic Nitrogen Fixation Dordrecht, The Netherlands: Kluwer Academic Publishers;
  18. Hinrichs D., Wetten M., Meuwissen T. H. 2006; An algorithm to compute optimal genetic contributions in selection programs with large numbers of candidates. J Anim Sci 84:3212–3218
    [Google Scholar]
  19. Hohle T. H., O'Brian M. R. 2009; The mntH gene encodes the major Mn2+ transporter in Bradyrhizobium japonicum and is regulated by manganese via the Fur protein. Mol Microbiol 72:399–409
    [Google Scholar]
  20. Hornung J. M., Jones H. A., Perry R. D. 1996; The hmu locus of Yersinia pestis is essential for utilization of free haemin and haem – protein complexes as iron sources. Mol Microbiol 20:725–739
    [Google Scholar]
  21. Humann J. L., Schroeder B. K., Mortimer M. W., House B. L., Yurgel S. N., Maloney S. C., Ward K. L., Fallquist H. M., Ziemkiewicz H. T., Kahn M. L. 2008; Construction and expression of sugar kinase transcriptional gene fusions by using the Sinorhizobium meliloti ORFeome. Appl Environ Microbiol 74:6756–6765
    [Google Scholar]
  22. Humann J. L., Ziemkiewicz H. T., Yurgel S. N., Kahn M. L. 2009; Regulatory and DNA repair genes contribute to the desiccation resistance of Sinorhizobium meliloti Rm1021. Appl Environ Microbiol 75:446–453
    [Google Scholar]
  23. Jefferson R. A., Burgess S. M., Hirsh D. 1986; Beta-glucuronidase from Escherichia coli as a gene-fusion marker. Proc Natl Acad Sci U S A 83:8447–8451
    [Google Scholar]
  24. Knobloch J. K., Nedelmann M., Kiel K., Bartscht K., Horstkotte M. A., Dobinsky S., Rohde H., Mack D. 2003; Establishment of an arbitrary PCR for rapid identification of Tn 917 insertion sites in Staphylococcus epidermidis: characterization of biofilm-negative and nonmucoid mutants. Appl Environ Microbiol 69:5812–5818
    [Google Scholar]
  25. Lynch D., O'Brien J., Welch T., Clarke P., Cuiv P. O., Crosa J. H., O'Connell M. 2001; Genetic organization of the region encoding regulation, biosynthesis, and transport of rhizobactin 1021, a siderophore produced by Sinorhizobium meliloti. J Bacteriol 183:2576–2585
    [Google Scholar]
  26. Meade H. M., Long S. R., Ruvkun G. B., Brown S. E., Ausubel F. M. 1982; Physical and genetic characterization of symbiotic and auxotrophic mutants of Rhizobium meliloti induced by transposon Tn 5 mutagenesis. J Bacteriol 149:114–122
    [Google Scholar]
  27. Miller J. H. 1972 Experiments in Molecular Genetics Cold Spring Harbor, NY: Cold Spring Harbor Laboratory;
  28. Ngok-Ngam P., Ruangkiattikul N., Mahavihakanont A., Virgem S. S., Sukchawalit R., Mongkolsuk S. 2009; Roles of Agrobacterium tumefaciens RirA in iron regulation, oxidative stress response, and virulence. J Bacteriol 191:2083–2090
    [Google Scholar]
  29. Noya F., Arias A., Fabiano E. 1997; Heme compounds as iron sources for nonpathogenic Rhizobium bacteria. J Bacteriol 179:3076–3078
    [Google Scholar]
  30. Persmark M., Pittman P., Buyer J. S., Schwyn B., Gill P. R. Jr, Neilands J. B. 1993; Isolation and structure of rhizobactin 1021, a siderophore from the alfalfa symbiont Rhizobium meliloti 1021. J Am Chem Soc 115:3950–3956
    [Google Scholar]
  31. Platero R., Peixoto L., O'Brian M. R., Fabiano E. 2004; Fur is involved in manganese-dependent regulation of mntA ( sitA) expression in Sinorhizobium meliloti. Appl Environ Microbiol 70:4349–4355
    [Google Scholar]
  32. Poole P. S., Blyth A., Reid C. J., Walters K. 1994; myo-Inositol catabolism and catabolite regulation in Rhizobium leguminosarum bv. viciae. Microbiology 140:2787–2795
    [Google Scholar]
  33. Rees D. C., Howard J. B. 2000; Nitrogenase: standing at the crossroads. Curr Opin Chem Biol 4:559–566
    [Google Scholar]
  34. Sambrook J., Fritsch E. F., Maniatis T. 1989 Molecular Cloning: a Laboratory Manual, 2nd edn. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory;
  35. Sangwan I., O'Brian M. R. 1992; Characterization of delta-aminolevulinic acid formation in soybean root nodules. Plant Physiol 98:1074–1079
    [Google Scholar]
  36. Schwede T., Kopp J., Guex N., Peitsch M. C. 2003; SWISS-MODEL: an automated protein homology-modeling server. Nucleic Acids Res 31:3381–3385
    [Google Scholar]
  37. Simon R., Priefer U., Pühler A. 1983 Vector Plasmids for In-Vivo and In-Vitro Manipulations of Gram-Negative Bacteria Edited by Pühler A. Berlin: Springer;
  38. Stojiljkovic I., Hantke K. 1994; Transport of haemin across the cytoplasmic membrane through a haemin-specific periplasmic binding-protein-dependent transport system in Yersinia enterocolitica. Mol Microbiol 13:719–732
    [Google Scholar]
  39. Todd J. D., Wexler M., Sawers G., Yeoman K. H., Poole P. S., Johnston A. W. 2002; RirA, an iron-responsive regulator in the symbiotic bacterium Rhizobium leguminosarum. Microbiology 148:4059–4071
    [Google Scholar]
  40. Viguier C., Cuív P. ó., Clarke P., O'Connell M. 2005; RirA is the iron response regulator of the rhizobactin 1021 biosynthesis and transport genes in Sinorhizobium meliloti 2011. FEMS Microbiol Lett 246:235–242
    [Google Scholar]
  41. Wexler M., Yeoman K. H., Stevens J. B., de Luca N. G., Sawers G., Johnston A. W. 2001; The Rhizobium leguminosarum tonB gene is required for the uptake of siderophore and haem as sources of iron. Mol Microbiol 41:801–816
    [Google Scholar]
  42. Wolk C. P., Cai Y., Panoff J. M. 1991; Use of a transposon with luciferase as a reporter to identify environmentally responsive genes in a cyanobacterium. Proc Natl Acad Sci U S A 88:5355–5359
    [Google Scholar]
  43. Yang J., Sangwan I., Lindemann A., Hauser F., Hennecke H., Fischer H. M., O'Brian M. R. 2006; Bradyrhizobium japonicum senses iron through the status of haem to regulate iron homeostasis and metabolism. Mol Microbiol 60:427–437
    [Google Scholar]
  44. Yurgel S. N., Kahn M. L. 2005; Sinorhizobium meliloti dctA mutants with partial ability to transport dicarboxylic acids. J Bacteriol 187:1161–1172
    [Google Scholar]
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