Dr. Shaun Lott

AgResearch Senior Lecturer in Structural Biology

AgResearch Senior Lecturer in Structural Biology

Structural Biology

Phone: +64 9 373-7599 ext 87074
Fax: +64 9 373-7414
Room 424A
Email: s.lott@auckland.ac.nz

See also https://unidirectory.auckland.ac.nz/profile/s-lott

Research Interests

I am interested in using structural analysis and a range of biochemical and biophysical tools to address important biological systems in agriculture and human health. Current projects in the lab fall into three main groups:

AgResearch projects, focusing on proteins of agricultural importance

ABC toxins

These toxins are composed of three core subunits (A, B and C) and are best characterised from insect pathogens such as Yersinia entomophaga. Jason Busby has determined the first structure of the BC sub-complex, work that was recently published in Nature (Busby et al. 2013). Together with the structure of the A subunit previously determined by electron microscopy (Landsberg and Jones 2011) and the structures of the associated chitinase enzymes (Busby et al. 2012), this gives us the first complete picture of this class of toxin. We are now working to produce engineered versions of the complex. This was is a collaboration with Mark Hurst at AgResearch and Michael Landsberg at the University of Queensland.

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Non-ribosomal peptides synthases

Non-ribosomal peptide synthases (NRPSs) are large modular enzymes that produce an extensive range of secondary metabolites in bacteria and fungi. Verne Lee determined the structure of an adenylation domain from the endophytic fungus Neotyphodium lolii, the first fungal structure to be determined (Lee et al. 2010). He is now investigating the structure and function of the first archaeal NRPS enzyme to be identified.
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Proteins from Mycobacterium tuberculosis known to be essential for pathogenesis

Tryptophan biosynthesis

The tryptophan biosynthetic pathway is essential for M. tuberculosis to cause disease, and may also have a role in the interaction of the bacterium with the host immune system. We have determined the structures of the enzymes that catalyse the first two steps in tryptophan biosynthesis, and have developed inhibitors against them (Castell et al. 2013). This work has been carried out by Dr Genevieve Evans in collaboration with Prof Bill Denny.

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Siderophore biosynthesis

M. tuberculosis scavenges iron from its host using the siderophore mycobactin. The first step in mycobactin synthesis is the production of salycilate. We have determined the structure of salycilate synthase (MbtI) and have developed some inhibitors of the enzyme is collaboration with Dr Richard Payne (Chi et al. 2012).

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We are also working on the regulation of cholesterol metabolism by the transcriptional regulators KstR and KstR2. This work is an ongoing collaboration with Sharon Kendall.


Proteins that regulate the human epithelial sodium channel (ENaC) - the primary point of regulation for blood pressure

WW-containing E3 ubiquitin ligases

The cell surface expression of the epithelial sodium channel (ENaC) is regulated by ubiquitylation vis the ubiquitin ligases Nedd4 and Nedd4-2. We have investigated the interaction of the WW domains of Nedd4 with the target peptides in ENaC, using SPR (Lott et al. 2002) and NMR analysis (Bobby et al. 2013).

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We are also working on the structure and function of COMMD proteins. This work is an ongoing collaboration with Fiona McDonald and Ezra Burstein.

References

  • Bobby, Romel, Karima Medini, Philipp Neudecker, Tet Verne Lee, Margaret A Brimble, Fiona J McDonald, J Shaun Lott, and Andrew J Dingley. 2013. “Structure and dynamics of human Nedd4-1 WW3 in complex with the αENaC PY motifBBA - Proteins and Proteomics 1834: 1632–1641. doi:10.1016/j.bbapap.2013.04.031.
  • Busby, Jason N, Michael J Landsberg, Robert M Simpson, Sandra A Jones, Ben Hankamer, Mark R H Hurst, and J Shaun Lott. 2012. “Structural Analysis of Chi1 Chitinase From Yen-Tc: the Multisubunit Insecticidal ABC Toxin Complex of Yersinia entomophaga.” Journal of Molecular Biology 415: 359–371. doi:10.1016/j.jmb.2011.11.018.
  • Busby, Jason N, Santosh Panjikar, Michael J Landsberg, Mark R H Hurst, and J Shaun Lott. 2013. “The BC Component of ABC Toxins Is an RHS-Repeat-Containing Protein Encapsulation Device.” Nature 501: 547–550. doi:10.1038/nature12465.
  • Castell, Alina, Francesca L Short, Genevieve L Evans, Tammie V M Cookson, Esther M M Bulloch, Dmitri D A Joseph, Clare E Lee, Emily J Parker, Edward N Baker, and J Shaun Lott. 2013. “The Substrate Capture Mechanism of Mycobacterium Tuberculosis Anthranilate Phosphoribosyltransferase Provides a Mode for Inhibition.” Biochemistry 52: 1776–1787. doi:10.1021/bi301387m.
  • Chi, Gamma, Alexandra Manos-Turvey, Patrick D O’Connor, Jodie M Johnston, Genevieve L Evans, Edward N Baker, Richard J Payne, J Shaun Lott, and Esther M M Bulloch. 2012. “Implications of Binding Mode and Active Site Flexibility for Inhibitor Potency Against the Salicylate Synthase From Mycobacterium Tuberculosis.” Biochemistry 51: 4868–4879. doi:10.1021/bi3002067.
  • Landsberg, M. J., Jones, S. A., Rothnagel, R., Busby, J. N., Marshall, S. D. G., Simpson, R. M., Lott, J. S., Hankamer, B., and Hurst, M. R. H. 2011. “3D Structure of the Yersinia entomophaga Toxin Complex and Implications for Insecticidal Activity”: Proc Natl Acad Sci USA 108, 20544–20549.
  • Lee, T Verne, Linda J Johnson, Richard D Johnson, Albert Koulman, Geoffrey A Lane, J Shaun Lott, and Vickery L Arcus. 2010. “Structure of a Eukaryotic Nonribosomal Peptide Synthetase Adenylation Domain That Activates a Large Hydroxamate Amino Acid in Siderophore Biosynthesis.” The Journal of Biological Chemistry 285: 2415–2427. doi:10.1074/jbc.M109.071324.
  • Lott, J Shaun, Sarah J Coddington-Lawson, Paul H Teesdale-Spittle, and Fiona J McDonald. 2002. “A Single WW Domain Is the Predominant Mediator of the Interaction Between the Human Ubiquitin-Protein Ligase Nedd4 and the Human Epithelial Sodium Channel.” The Biochemical Journal 361: 481–488.