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People

Dr Paul Dobbin

Lecturer
School of Life Sciences
Dr Paul Dobbin

Profile

Biography

Career details 2001 - present Lecturer in Biochemistry, Dept. of Biological Sciences, University of Essex 1993 - 2000 Senior Research Associate, School of Biological Sciences, UEA Norwich 1987 - 1992 Research Assistant, Dept. of Pharmacy, King's College London PhD (London) 1992 - Medicinal Chemistry. Thesis title Chelators Suitable for the Nutritional Supply of Metals BSc Hons (Leicester) 1986 - Chemistry teacher of bioinorganic and organic chemistry on undergraduate courses run by The Department of Biological Sciences member of The Biochemical Society and The Society for General Microbiology reviewer for various journals, including Microbiology, Archives of Microbiology and FEMS Microbiology Letters Contact details I am always happy to hear from prospective PhD students, Postdoctoral workers, and academic or industrial collaborators Contact address: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK

Research and professional activities

Research interests

In the late 1980's it was first demonstrated that the anaerobic growth of Shewanella and Geobacter species could be supported by using insoluble Fe(III) as a respiratory substrate. These findings attracted attention from bioenergeticists, who were curious to know how electrons were transferred from primary dehydrogenases to the cell exterior with the concomitant generation of a proton electrochemical gradient. Subsequent experiments have revealed that electron transport to Fe(III) in Shewanella is via a network of multiheme c-type cytochromes, located at the inner membrane, in the periplasmic compartment, and at the outer membrane (where the terminal reduction of Fe(III) to Fe(II) occurs). Workers in the nuclear power industry are also interested in Fe(III) respiring microorganisms due to their tendency to reduce other metal cations, including soluble U(VI) and Tc(VII), which are then precipitated as insoluble lower valence forms.

We are currently investigating the structures and functions of Shewanella multiheme cytochromes by a variety of techniques, including: (1) X-ray crystallography, which has yielded the molecular structure of an iron-induced flavocytochrome c3 (Ifc3); (2) magneto-optical spectroscopies (UV-VIS, EPR, MCD), which have shown the cytochromes to normally feature low-spin bis-His ligated c-hemes; (3) electochemistry, which has demonstrated different routes of electron passage into Ifc3, and has the potential for monitoring reconstitution of the electron transport chain to Fe(III) in vitro; and (4) protein engineering, which will enable identification of amino acid residues that are crucial to the cytochromes' involvement in Fe(III) respiration.

We have noted a number of cytochromes in Shewanella to be specifically synthesised during growth with Fe(III), including the aforementioned Ifc3. Recent experiments have identified a transcription factor of the LysR family to positively regulate Ifc3 expression, and we are currently studying in more detail the molecular basis for Fe(III) responsive gene transcription in the bacterium.

The importance of Fe(III) respiration has been recognized by the United States Department of Energy (DOE), who are funding the sequencing of the Shewanella putrefaciens MR-1 and Geobacter sufurreducens genomes. Exploitation of pre-published data generated in these programs is enabling us to identify the range of redox proteins involved in the anaerobic respiration of Fe(III) and other substrates by the use of 2D gel electrophoresis, microarray gene hybridization, and chromosomal mutations.

Geobacter species also have potential applications in the field of bioremediation, which arise from their ability to couple the reduction of Fe(III) with the complete oxidation (to carbon dioxide) of petroleum components such as benzene and toluene under the anoxic conditions normally prevalent in polluted sites. We are currently seeking to identify and characterize the novel proteins involved in the anaerobic degradation of aromatic hydrocarbons by Geobacter using the genomic and proteomic techniques mentioned above.

Finally, we are attempting to isolate novel Fe(III) respiring bacteria from microbial communities present in a number of different habitats. These include the human colonic microflora, where the reduction of Fe(III) to Fe(II) might lead to the onset of inflammatory disease states in the large intestine.

Our studies on bacterial Fe(III) respiration in the Department of Biological Sciences at Essex are aided by external collaborations with: Workers in the Centre for Metalloprotein Spectroscopy and Biology, University of East Anglia, Norwich, which is jointly directed by Dr David Richardson and Prof Andrew Thomson, FRS; Prof Graeme Reid and co-workers in the Institute of Cell and Molecular Biology, University of Edinburgh

Current research

My studies are centered on the biochemistry, physiology, and genetics of bacterial Fe(III) respiration. This anaerobic process is of ecological importance in a variety of soils and sediments, and moreover has potential uses in bioremediation. Work currently being undertaken includes:

structural and spectroscopic characterisation of multiheme cytochromes involved in Fe(III) respiration by Shewanella and Geobacter species

heterologous expression and protein engineering of these cytochromes

investigation of the molecular basis for Fe(III)-responsive gene transcription in Shewanella

the use of 2D gel electrophoresis, microarray gene hybridization, and chromosomal mutations to identify the range of redox proteins proteins involved in Fe(III) respiration

isolation and characterisation of novel Fe(III) respiring bacteria from different habitats

investigation of the potential for Fe(III) respiration amongst the human colonic microflora

Teaching and supervision

Current teaching responsibilities

  • General and Organic Chemistry (BS132)

  • Inorganic and Physical Chemistry (BS133)

  • Transferable Skills in Life Sciences (BS143)

  • Employability skills for Biomedical Scientists (BS214)

  • Clinical Biochemistry (BS237)

  • Issues in Biomedical Science (BS306)

  • Research Project in Biomedical Science (BS831)

  • Research Project in Life Sciences (BS832)

Previous supervision

Tatiana De Vasconcelos Porto
Tatiana De Vasconcelos Porto
Thesis title: Structural and Kinetic Studies of a Copper Sensor Protein in Streptomyces Lividans
Degree subject: Biochemistry
Degree type: Doctor of Philosophy
Awarded date: 21/3/2016

Publications

Journal articles (5)

Battah, S., Hider, RC., MacRobert, AJ., Dobbin, PS. and Zhou, T., (2017). Hydroxypyridinone and 5-Aminolaevulinic Acid Conjugates for Photodynamic Therapy. Journal of Medicinal Chemistry. 60 (8), 3498-3510

Manole, A., Kekilli, D., Svistunenko, DA., Wilson, MT., Dobbin, PS. and Hough, MA., (2015). Conformational control of the binding of diatomic gases to cytochrome c′. JBIC Journal of Biological Inorganic Chemistry. 20 (4), 675-686

Servid, AE., McKay, AL., Davis, CA., Garton, EM., Manole, A., Dobbin, PS., Hough, MA. and Andrew, CR., (2015). Resonance Raman Spectra of Five-Coordinate Heme-Nitrosyl Cytochromesc′: Effect of the Proximal Heme-NO Environment. Biochemistry. 54 (21), 3320-3327

Mason, MG., Shepherd, M., Nicholls, P., Dobbin, PS., Dodsworth, KS., Poole, RK. and Cooper, CE., (2009). Cytochrome bd confers nitric oxide resistance to Escherichia coli. Nature Chemical Biology. 5 (2), 94-96

Casas, A., Battah, S., Di Venosa, G., Dobbin, PS., Rodriguez, L., Fukuda, H., Batlle, A. and MacRobert, AJ., (2009). Sustained and efficient porphyrin generation in vivo using dendrimer conjugates of 5-ALA for photodynamic therapy. Journal Of Controlled Release. 135 (2), 136-143

Grants and funding

2008

Synthesis of Therapeutic Agents

Engineering & Physical Sciences Res.Council

Contact

pdobbin@essex.ac.uk
+44 (0) 1206 874867

Location:

3SW.5.11, Colchester Campus