For my China Scholarship Council-funded studentship, I am probing the structure and function of the cyanobacterial homologue of Chloroplast Sensor Kinase (CSK), called Histidine Kinase 2 (Hik2). These types of kinase belong to a family of closely regulated and significant signal transduction cellular processes known as two-component systems, critical for organisms to sense, and then respond rapidly to, fluctuating changes in their native environments.
Previously, CSK was shown to function as a novel redox sensor kinase in the chloroplasts of green plants, through the use of the model plant Arabidopsis thaliana. In my project, I am building upon the knowledge that Hik2 has been shown to control transcription of genes coding for photosystems in cyanobacteria. Properties of Hik2, initially predicted by John Allen and co-workers (the CoRR hypothesis) to be crucial in the efficient functioning of the chloroplastic and mitochondrial genomes, are now likely to be focused upon other response/regulatory mechanisms within the cyanobactera under study.
Following detailed biochemical characterisations, I now aim to determine the three-dimensional structures of both the modified and the unmodified forms of the full-length Hik2 protein and a variety of observed structural populations (co-supervision by Dr Nield and Dr Krauss). My training in negative stain transmission electron microscopy (TEM) has proven fruitful in recording Hik2 complexes in a variety of forms, with additional analyses in silico, with the ultimate goal to reveal functional, and mechanistic, detail.