Macromolecular Crystallography (MX) beamlines are complex experimental stations that need to be kept up to date with the latest technology to provide the best possible beam performance and data. I am very interested in developing technology that improves the performance of our experimental stations. We have recently improved our visualisation hardware to allow users to see their samples better and to align them to the beam with much greater precision. In addition, an automated LN2 washing system is being tested. This will allow users to remove clear superficial ice from their samples if it has accumulated during transport.
In recent years we have seen huge advances in x-ray crystallography including technical advancement in MX beamlines around the world. But as projects become more challenging (with more membrane proteins and large complexes being studied), well diffracting samples are becoming more difficult to come by. For this reason a great number of structures require much more time and effort to obtain a positive outcome, and some may benefit from specialised techniques to improve their diffraction properties.
Some of these techniques can be applied post crystal growth and profit from the dynamic nature of macromolecular crystals. These techniques include soaking the crystal with different compounds, chemical cross-linking, crystal annealing and dehydration. Crystals are capable of short and (sometimes) long-range rearrangements that can, in certain cases, lead to greater internal order, lower solvent content or even a change in space group. These lattice changes may result in improved diffraction or a higher quality data set.
I would like to undertake controlled and systematic studies of the effect of these techniques to provide the MX community with valuable information that can be generally applied when the crystals obtained are proving to be challenging. Currently my main focus is on the effect dehydration has on crystal packing and its relation to diffraction quality. I have been involved in the development of a dehydration device (HC1) that can be operated within the beamline environment. We have established collaboration with the EMBL-Grenoble in France and the Max-Lab in Sweden to develop, test and maintain these devices in our respective beamlines and to make this technology available to our user communities.
PQQ dependent quinoproteins
PQQ dependent quinoproteins are bacterial dehydrogenases distinct from NAD and FAD dependent ones. They convert a range of sugars, alcohols and even amines into their corresponding lactones. Furthermore, they catalyse a series of reactions in bacteria whose relevance is not wholly understood.
My main research interest in this area has focused on understanding the structural determinants that modulate substrate selectivity in a Soluble Glucose Dehydrogenase from A. calcoaceticus. This enzyme is used in commercial blood glucose sensors and my work is being undertaken in collaboration with an industrial partner. I would like to complete certain aspects of this work and widen the scope of the project to study other members of this interesting family of proteins. A number of targets have been selected and are undergoing cloning and expression testing at the moment.