BBSRC DTG CASE PhD Studentship - The Role of SecA2 in Targeting Substrates to the Sec-dependent Protein Translocase

Postgraduate Opportunities

Newcastle University

Supervisor(s): Professor Colin Harwood, Dr Michael Rasmussen
Institute: Institute for Cell and Molecular Biosciences
Co-sponsor: Delta Biotechnology Ltd

Between 5-10% of the proteins encoded by a bacterium are typically secreted across the cytoplasmic membrane, primarily via the Sec-dependent pathway. These include enzymes involved in cell wall synthesis and cell division. The ability of pathogenic bacteria to cause disease is strongly associated with their ability to secrete proteins that enables them to: (i) interact with and subvert their target host; (ii) avoid of the innate immune response; (iii) produce toxins. Consequently, the Secdependent secretion translocase, comprising proteins SecAYEG, is essential for cell viability and the ability to cause disease. A key component of the Sec translocase is SecA, which is responsible for identifying secretory proteins and targeting them to the membrane spanning component of the translocase.

We have shown that members of the B. cereus group encode a second SecA2 that specifically targets surface layer proteins. This project will study the binary interactions between SecA2 and its substrates and the tertiary interactions between SecA2/substrate and the pore-forming component of the translocase, namely SecY. This will be achieved by constructing chimeric versions of SecA and SecA2, and analysing the interactions between these chimeras and (i) a model SecA2-dependent secretory protein and, (ii) SecY. A secondary aim will be to develop the secondary translocase as a substrate-specific translocase for the secretion of industrial enzymes and heterologous proteins.

Further Reading
Harwood, CR. & Cranenburgh, R. (2008) Bacillus protein secretion, an unfolding story. Trends in Microbiology 16: 41-88.

Harwood, C.R. (2007) Bacillus subtilis as a model for bacterial systems biology. In, Encyclopaedia of Life, John Wiley and Sons, Chichester
http://www.els.net DOI: 10.1002/9780470015902.a0002027.

Craddock, T., Lord, P., Harwood, C.R. and Wipat, A. (2006). e-Science Tools For The Genomic Scale Characterisation of Bacterial Secreted
Proteins. Proceedings of the 5th UK e-Science All hands Meeting.

Antelmann, H., Williams, R.C., Miethke, M., Albrecht, D., Harwood, C.R. & Hecker, M. (2005). The extracellular and cytoplasmic proteomes of the non-virulent Bacillus anthracis strain UM23C1-2. Proteomics 5, 3684-3695.

Sarvas, M., Harwood, C.R., Bron, S. & van Dijl, J.M. (2004). Post-translocational folding of secretory proteins in Gram-positive bacteria.
Biochimica et Biophysica Acta, Molecular Cell Research (Special Issue on Protein Export/Secretion in Bacteria) 1694, 311-327.

Williams, R.C. Rees, M.L., Jacobs, M.F., Prágai, Z., Thwaite J.E., Baillie L.W.J., Emmerson, P.E. & Harwood, C.R. (2003) Production of
Bacillus anthracis protective antigen is dependent on the extracellular chaperone, PrsA. Journal of Biological Chemistry 278, 18056 – 18062.

Person Specification
Applicants should hold or expect to obtain a first-class or upper-second-class Honours degree in a relevant discipline.

Value of the Award and Eligibility
Due to funding criteria, this award is only available to UK and EU applicants. The award for UK students covers fees and a stipend. The award for EU applicants covers fees only.

How to Apply
Please complete the University's postgraduate application form (www.ncl.ac.uk/postgraduate/apply) quoting the reference number CMB39 and selecting PhD in the Faculty of Medical Sciences - Cell and Molecular Biosciences as the programme of study. Only mandatory fields need be completed (no personal statement required) and your CV and covering letter should be attached to the form. You should also send a CV and covering letter to Louise Campbell, l.e.campbell@ncl.ac.uk. Your covering letter should state the title and the reference number of the studentship (CMB39).

Closing Date
Applications will be considered until a suitable candidate is appointed.

Further Information
Please direct general enquiries to Mrs Louise Campbell, l.e.campbell@ncl.ac.uk, Postgraduate Secretary, Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH.

For further information regarding the studentship please Professor Colin Harwood, colin.harwood@ncl.ac.uk