Towards the end of 2016, the Jackson lab headed out to Bungonia National Park to make the most of the warmer weather. Ever efficient, the E3 team took the opportunity to catch blowflies for genomic analysis along the way.
The hike was also a chance to say goodbye to a few Jackson lab members who were departing. PhD students Ben, Nick, Jason and Elena completed their time with the group at the end of 2016, as did honours students Jen and Janelle.
The hike into Bungonia gorge was treacherous and tiring, but the group was rewarded with a swim in an idyllic river at the bottom.
While our resident hike-planner (Nick) has departed, there will certainly be more compulsory fun scheduled for 2017.
Happy New Year!
Congratulations to Drs Dongdi Li, Hafna Ahmed and William Zhang on their recent graduation.
Congratulations to Nansook, who published a paper in Biochemistry together with collaborators from the Tokuriki lab: “Conformational tinkering drives evolution of a promiscuous activity through indirect mutational effects”. [link]
In this work, we used laboratory evolution to effect a thousand-fold increase in phosphotriesterase activity in a lactonase enzyme. Mutations acquired during evolution altered the position of an active site residue that previously had no functional role, improving the alignment of the substrate in the active site and thereby increasing phosphotriesterase activity. This work gives a detailed picture of how “conformational tinkering” by remote mutations can allow large increases in enzyme activity.
Congratulations to Peter, whose paper “Sensing and signaling of oxidative stress in chloroplasts by inactivation of the SAL1 phosphoadenosine phosphatase” was published in PNAS [link]. This work was done with a number of collaborators, including the Pogson group at the ANU Research School of Biology.
When adverse conditions like drought cause oxidative stress in plant chloroplasts, a chemical messenger originating from the chloroplast induces a stress response in the plant. Our work shows how oxidative stress is detected and converted to this chemical stress signal: oxidative stress inactivates the enzyme that eliminates the stress signal, allowing it to accumulate.
Pete and Kai explain the potential applications for drought resistance in crops:
Congratulations to Hafna, Elaaf and Brendon, whose paper “Rv2074 is a novel F420H2-dependent biliverdin reductase in Mycobacterium tuberculosis” was published in Protein Science. [link]
In this work, we identified and characterised a biliverdin reductase from Mycobacterium tuberculosis, and elucidated its catalytic mechanism. This enzyme produces a potent antioxidant, bilirubin, using biliverdin, which is produced in large amounts in macrophages infected with mycobacteria. Thus, biliverdin reductase could contribute to the persistence of M. tuberculosis in macrophages (the cause of latent tuberculosis infection) by protecting the bacterium from oxidative stress.
Catching up on some old lab news: William Zhang, Dongdi Li, Nansook Hong and Elaaf Mohamed have all recently submitted their PhD theses. Congratulations everyone!
We also welcome Jules Kirk to the lab as an Honours student.
Congratulations to Galen and the E3 team whose paper “Mapping the accessible conformational landscape of an insect carboxylesterase using conformational ensemble analysis and kinetic crystallography” has been published in Structure.
Using automated multi-conformer modelling and ensemble refinement, we uncovered a dynamically coupled network important for catalysis in an organophosphate-degrading enzyme, and using kinetic crystallography, we could monitor the release of a covalently bound intermediate in “slow motion”. This work shows how crystallographic tools can be used to explore the conformational landscape of an enzyme at each step in a complex catalytic cycle.