Juan Sanchez-Weatherby

Synchrotron instrumentation

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.

Crystal dehydration

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.

1. Inducing phase changes in crystals of macromolecules: Status and perspectives for controlled crystal dehydration. Russi S, Juers DH, Sanchez-Weatherby J, Pellegrini E, Mossou E, Forsyth VT, Huet J, Gobbo A, Felisaz F, Moya R, McSweeney SM, Cusack S, Cipriani F, Bowler MW. J Struct Biol. DOI: 10.1016/j.jsb.2011.03.002 (2011)
2. Structural basis for MOF and MSL3 recruitment into the dosage compensation complex by MSL1, Jan Kadlec, Erinc Hallacli, Michael Lipp, Herbert Holz, Juan Sanchez-Weatherby, Stephen Cusack, Asifa Akhtar, Nature Structural and Molecular Biology DOI: 10.1038/nsmb.1960 (2011)
3. Improving diffraction by humidity control: a novel device compatible with X-ray beamlines, J. Sanchez-Weatherby, MW Bowler, J Huet, A Gobbo, F. Felisaz, B Lavault, R Moya, J Kadlec, R B-G Ravelli, F Cipriani, (2009). Acta Cryst. D 65(12): 1237-1246.
4. Crystallization of quinoprotein glucose dehydrogenase variants and homologues by microseeding J Sanchez-Weatherby, S Southall, A Oubrie, (2006). Acta Cryst F 62: 518-521.
5. Distinctive properties of the catalase B of Aspergillus nidulans JA Calera, J. Sanchez-Weatherby, R Lopez-Medrano, F Leal, et al. (2000). FEBS Lett 475(2): 117-120.

I completed my undergraduate study of Biology at the University of Salamanca, Spain in 1998. The two following years I was involved in a post-graduate research project working with fungi called “Purification and Immunochemical Characterization of the ASPND1 Antigen of Aspergillus nidulans”, supervised by Dr. Fernando Leal. In 2003 I changed field and country, and undertook an MRes in Structural Biology at Birkbeck College, London, under the title of “Purification and crystallisation of two catalytic mutants of the mitochondrial Holliday Junction resolvase Ydc2 from Schizosaccharomyces pombe” supervised by Dr. Tracey Barrett.

In 2003 I started my PhD at the University of East Anglia, Norwich under the supervision of Dr. Arthur Oubrie and Prof. David Richardson, and completed it in 2006 with the title “Structural determination of maltose/glucose specificity in sGDH from Acinetobacter calcoaceticus”. Then in 2006 I moved to the EMBL outstation in Grenoble and worked, under the supervision of Florent Cipriani, as a post-doctoral fellow in the development and testing of novel synchrotron instrumentation. This work lead to the development of the HC1, a device that is currently used in numerous macromolecular beamlines and labs around the world.

In early 2008 I moved to Diamond as beamline scientist in I02. I am responsible, with others, for the smooth running of the beamline, including user support and training. I am also involved in my own independent research in structural biology, and responsible for the implementation and commissioning of new equipment and the development of new experimental techniques, to allow users to undertake better science.