John Innes Centre

Prof Ray Dixon

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Curriculum Vitae

  • 1969 B.Sc.: Microbiology, University of Reading
  • 1973 D.Phil.: Microbial Genetics, University of Sussex,
  • 1973-1975 Postdoctoral Fellow, University of Sussex
  • 1976-1995 Research Scientist: Nitrogen Fixation Laboratory, University of Sussex
  • 1995-2009 Project Leader and Professor of Molecular Microbiology: John Innes Centre, Norwich
  • 1983 Fleming Award, Society for General Microbiology
  • 1987 Elected member of EMBO
  • 1999 Fellow of the Royal Society
  • 2010-present Head of Department, Dept of Molecular Microbiology, John Innes Centre, UK

Ray Dixon

Head of Department

Molecular Microbiology

Contact details

Tel: +44 (0)1603 450747
ray.dixon@bbsrc.ac.uk

Research interests

The ability of bacteria to respond to a multitude of environmental signals and integrate these signals to trigger adaptive responses provides a successful strategy for survival in rapidly changing environments.

Understanding the molecular mechanisms by which these signals are perceived and integrated is the main aim of our work. We are analysing multi-protein signalling complexes in which interactions are modulated by redox changes, ligand binding and covalent modification.

Our major emphasis is on signal transduction cascades that regulate nitrogen fixation genes in response to oxygen, carbon and fixed nitrogen status. We also study a specific class of prokaryotic transcription factors that use energy from nucleotide hydrolysis to drive the process of transcription initiation. These bacterial enhancer binding proteins interact at a distance with RNA polymerase holoenzyme containing an unusual sigma factor, sigma54. One such protein under study (in collaboration with Stephen Spiro, Dallas, USA) is NorR, a nitric oxide responsive  transcriptional activator that controls expression of genes required for NO detoxification. Enhancer binding proteins contain a variety of sensory modules that probably contribute to the adaptability and unique physiological diversity of many bacteria.

Selected Publications

Slavny P., Little R., Salinas P., Clarke T. A., Dixon R. (2009)
Quaternary structure changes in a second PAS domain mediate intramolecular redox signal relay in the NifL regulatory protein
Molecular Microbiology 75 (1) 61-75
DOI:10.1111/j.1365-2958.2009.06956.x
Tucker N. P., D'Autreaux B., Yousafzai F. K., Fairhurst S. A., Spiro S., Dixon R. (2008)
Analysis of the nitric oxide-sensing non-heme iron center in the NorR regulatory protein
Journal of Biological Chemistry 283 908-918
Little R., Martinez-Argudo I., Perry S., Dixon R. (2007)
Role of the H domain of the histidine kinase-like protein NifL in signal transmission
Journal of Biological Chemistry 282 13429-13437
D'Autreaux B., Tucker N. P., Dixon R., Spiro S. (2005)
A non-haem iron centre in the transcription factor NorR senses nitric oxide
Nature 437 769-772
Perry S., Shearer N., Little R., Dixon R. (2005)
Mutational analysis of the nucleotide-binding domain of the anti-activator NifL
Journal of Molecular Biology 346 935-949
Dixon R., Kahn D. (2004)
Genetic regulation of biological nitrogen fixation.
Nature Reviews Microbiology 2 621-631
Martinez-Argudo I., Little R., Dixon R. (2004)
A crucial arginine residue is required for a conformational switch in NifL to regulate nitrogen fixation in Azotobacter vinelandii.
Proceedings of the National Academy of Sciences USA 101 16316-16321
Little R., Dixon R. (2003)
The amino-terminal GAF domain of Azotobacter vinelandii NifA binds 2-oxoglutarate to resist inhibition by NifL under nitrogen-limiting conditions.
Journal of Biological Chemistry 278 28711-28718
Studholme D. J., Dixon R. (2003)
Domain architectures of sigma54-dependent transcriptional activators.
Journal of Bacteriology 185 1757-1767
Little R., Colombo V., Leech A., Dixon R. (2002)
Direct interaction of the NifL regulatory protein with the GlnK signal transducer enables the Azotobacter vinelandii NifL-NifA regulatory system to respond to conditions replete for nitrogen.
Journal of Biological Chemistry 277 15472-15481
Little R., Reyes-Ramirez F., Zhang Y., van Heeswijk W. C., Dixon R. (2000)
Signal transduction to the Azotobacter vinelandii NIFL-NIFA regulatory system is influenced directly by interaction with 2-oxoglutarate and the PII regulatory protein.
EMBO Journal 19 6041-6050

Recent Publications

Bush M., Ghosh T., Tucker N., Zhang X., Dixon R. (2010)
Nitric oxide-responsive inter-domain regulation targets the sigma(54)- interaction surface in the enhancer binding protein NorR.
Molecular Microbiology
DOI:10.1111/j.1365-2958.2010.07290.x
Tucker N. P., Le Brun N. E., Dixon R., Hutchings M. I. (2010)
There's NO stopping NsrR, a global regulator of the bacterial NO stress response
Trends in Microbiology 18 (4) 149-156
DOI:10.1016/j.tim.2009.12.009
Hervás A. B., Canosa I., Little R., Dixon R., Santero E. (2009)
NtrC-dependent regulatory network for nitrogen assimilation in Pseudomonas putida.
Journal of Bacteriology 191 (19) 6123-6135
DOI:10.1128/JB.00744-09
Oliveira M. A., Baura V. A., Aquino B., Huergo L. F., Kadowaki M. A., Chubatsu L. S., Souza E. M., Dixon R., Pedrosa F. O., Wassem R., Monteiro R. A. (2009)
Role of conserved cysteine residues in Herbaspirillum seropedicae NifA activity.
Research in Microbiology 160 (6) 389-395
DOI:10.1016/j.resmic.2009.06.002
Setubal J. C., dos Santos P., Goldman B. S., Ertesvċg H., Espin G., Rubio L. M., Valla S., Almeida N. F., Balasubramanian D., Cromes L., Curatti L., Du Z., Godsy E., Goodner B., Hellner-Burris K., Hernandez J. A., Houmiel K., Imperial J., Kennedy C., Larson T. J., Latreille P., Ligon L. S., Lu J., Maerk M., Miller N. M., Norton S., O'Carroll I. P., Paulsen I., Raulfs E. C., Roemer R., Rosser J., Segura D., Slater S., Stricklin S. L., Studholme D. J., Sun J., Viana C. J., Wallin E., Wang B., Wheeler C., Zhu H., Dean D. R., Dixon R., Wood D. (2009)
Genome sequence of Azotobacter vinelandii, an obligate aerobe specialized to support diverse anaerobic metabolic processes.
Journal of Bacteriology 191 (14) 4534-4545
DOI:10.1128/JB.00504-09
Tucker N. P., Ghosh T., Bush M., Zhang X., Dixon R. (2009)
Essential roles of three enhancer sites in {sigma}54-dependent transcription by the nitric oxide sensing regulatory protein NorR.
Nucleic Acids Research 38 (4) 1182-1194
DOI:10.1093/nar/gkp1065
D'Autréaux B., Tucker N., Spiro S., Dixon R. (2008)
Characterization of the nitric oxide-reactive transcriptional activator NorR
Methods in Enzymology: Globins and other Nitric Oxide-Reactive Proteins, Part B 437 235-251
DOI:10.1016/S0076-6879(07)37013-4
Tucker N. P., Hicks M. G., Clarke T. A., Crack J. C., Chandra G., Le Brun N. E., Dixon R., Hutchings M. I. (2008)
The transcriptional repressor protein NsrR senses nitric oxide directly via a [2Fe-2S] cluster.
PLoS ONE 3 (11) e3623
DOI:10.1371/journal.pone.0003623