Read the paper here!
Cataracts, the clouding of the eye lens, is a leading cause of blindness and visual impairments worldwide. Cataracts form when oxidative stress in the lens causes lens proteins, such as crystallin, to destabilise and aggregate. The molecular basis for the oxidation-induced aggregation of these proteins, however, has remained elusive. In this paper, recently published in the Journal of Molecular Biology, we use X-ray crystallography and small-angle X-ray light scattering to describe the structure of a disulfide-linked dimer of human gammaS-crystallin. This disulfide-linked dimer is prone to forming aggregates and would likely be prevalent in aging eyes. These findings provide insight into how oxidative modification of crystallins contributes to cataract formation.
This work was a collaboration with, and led by, members of the Carver Group at the Australian National University. Congratulations to all involved!
Congratulations to Nansook and everyone involved in this project! This has been a great collaboration with Lynn Kamerlin (Uppsala University), Chris Easton (ANU) and Michelle Coote’s (ANU) groups.
In this work, we follow changes in conformational sampling, electrostatic preorganization, and quantum tunneling along the evolutionary trajectory of a designed Kemp eliminase. We observe that in the Kemp Eliminase KE07, instability of the designed active site leads to the emergence of two additional active site configurations. Evolutionary conformational selection then gradually stabilizes the most efficient configuration, leading to an improved enzyme. This work exemplifies the link between conformational plasticity and evolvability and demonstrates that residues remote from the active sites of enzymes play crucial roles in controlling and shaping the active site for efficient catalysis.
Come and work with us on an exciting, collaborative project at the Australian National University!
The ANU Grand Challenge Research Program on Novel Miniaturized Medical Sensor Technology is now advertising Postdoctoral Fellow / Research Fellow positions located each in the Research Schools of Chemistry, Engineering, and Physics to work on the development of novel miniaturized biomedical sensors that can be integrated into wearable and point-of-care devices. These positions will work synergistically with the ANU Grand Challenge team benefitting from the breadth of the research programs and expertise. This project aims to revolutionise personalised medicine by providing new means for non-invasive collection and analysis of health data including the development of miniaturized sensors for detection of biomarkers in multiple sclerosis and diabetes.
The Research School of Chemistry Research Fellow will work in Associate Professor Colin Jackson’s group, and be responsible for design, engineering, and production of proteins as a key component of these biosensors. This could include engineering binding selectivity, optimizing ligand affinity, and chemical modification of the protein to function as part of a complex matrix, such as protein hydrogels.
For more details on how to apply, please follow this link: http://jobs.anu.edu.au/cw/en/job/526630/postdoctoral-fellow
Congratulations to Galen Correy who submitted his PhD thesis last week! Here he is clicking on the ‘submit’ button. Well done Galen!
Check out a few of Galen’s papers:
- Correy, G., Zaidman, D., Carvalho, S., Mabbitt, P. D., James, P. J., Kotze, A. C., … Jackson, C. J. (2017). Overcoming insecticide resistance through computational inhibitor design. bioRxiv (Pre-print).
- Correy, G.J., Carr, P.D., Meirelles, T., Mabbitt, P.D., Fraser, N.J., Weik, M., Jackson, C.J. (2016) Mapping the accessible conformational landscape of an insect carboxylesterase using kinetic crystallography and conformational ensemble analysis. Structure 24, 977-987.
- Correy, G.J.*, Mabbitt, P.D.*, Meirelles, T., Fraser, N.J., Coote, M.L., Jackson, C.J. (2016) Conformational disorganization within the active site of a recently evolved organophosphate hydrolase limits its catalytic efficiency. Biochemistry 55, 1408-1417. *contributed equally.
- Campbell, E., Correy, G., Mabbitt, P., Buckle, A., Tokuriki, N., Jackson, C. (2018). Laboratory evolution of protein conformational dynamics. Current Opinion in Structural Biology, 50, 49–57.
Ex-Jackson group member Dr. Ben Clifton has been awarded the ‘ANU Research School of Chemistry Director’s award for the Best Thesis 2017’. Ben’s PhD thesis ‘Functional evolution of solute-binding proteins’ describes the use of ancestral protein reconstruction to explore the molecular evolution of binding specificity and catalysis in amino-acid binding proteins.
You can find some of Ben’s published work here:
Link to paper
The amino acid glycine is an important inhibitory neurotransmitter and co-agonist of the N-methyl-D-aspartate receptors involved in synaptic plasticity. In this work, published in Nature Chemical Biology, we describe the computational design, development, and application of the first optical sensor for glycine. This FRET sensor can be used with single and two-photon excitation fluorescence microscopy. Here, we show that it can be used in combination with electrophysiology to investigate the spatial distribution of glycine in the extracellular space, and to probe how glycine concentrations change in response to plasticity-inducing stimuli.
This work was done in collaboration with Christian Henneberger’s group (University of Bonn, Institute of Cellular Neurosciences). Congratulations to Will, Michel and everyone involved in this work.
Jake Saunders and Mahakaran Sandhu have recently started their Honours projects in the Jackson Lab! Both Jake and Mahakaran have previously done projects in our group, and we are looking forward to sharing the lab with them again!
Congratulations to Tiffany Chau, who has recently finished off a challenging but rewarding Honours year in the Jackson Lab! Well done Tiffany!
Colin and Jules have recently published a chapter, with Thomas Huber (ANU), about using non-canonical amino acids for the modulation of enzyme activity. This chapter, published in Modern Biocatalysis: Advances Towards Synthetic Biological Systems (RSC Publishing), outlines the use of unnatural amino acids (UAAs) in protein engineering. Examples of how UAAs have successfully been used to engineer proteins for enhanced thermostability, catalytic efficiency, specificity and selectivity are provided, and remaining challenges within the field are discussed. This work also describes the engineering of tRNA synthetases for the site-specific incorporation of UAAs into proteins.
The chapter can be found here.
Immobilizing enzymes on a solid support can help improve their stability, rendering them more suitable for industrial and medical applications. However, standard covalent attachment approaches can be costly, often require many steps, and commonly lead to unfavourable orientations of the enzymes on the solid media. In this work, recently published in Advanced Biosystems, we produced enzyme-hydrogel complexes using anionic hydrogels and an engineered cationic supercharged phosphotriesterase. We show this system is capable of detoxifying organophosphates and catalyzing enantioselective reactions, and is remarkably robust and long-lasting (even when exposed to organic solvents). Additionally, degraded enzyme can be easily stripped from the gel and replaced with fresh protein, resulting in a very flexible system that could be readily scaled up for use in industry, synthesis, and bioremediation. Congratulations to Eleanor and everyone involved with this project.