Juan Sanchez-Weatherby
Macromolecular Crystallography
Juan Sanchez-Weatherby is a beamline scientist on the Macromolecular Crystallography Beamline I02. Juan joined Diamond at the end of 2008 from European Molecular Biology Lab (EMBL), in Grenoble, France where he undertook post-doctoral research at the Instrumentation Team. Previous to this he spent 4 years at the University of East Anglia investigating structural aspects of substrate selectivity in a PQQ-dependant soluble glucose dehydrogenase.
Email: Juan Sanchez-Weatherby
Tel: +44 (0) 1235 778661
MX Beamlines
Key Research Areas
Structural Biology, Synchrotron Instrumentation
Current Research Interests
Synchrotron instrumentation
Macromolecular Crystallography (MX) beamlines are complex experimental stations that need to be kept up to date with the latest technology to provide state of the art equipment and beam performance ensuring the best possible data. I am very interested developing equipment/technology that improves the performance of our stations experimental stations. We are currently improving our visualisation hardware to allow users to see their samples better and to be able to align them to the beam with much greater precision. Also, work is underway to modify the current beamstops for smaller and more precise ones, allowing for collection of better quality data. 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 – even if they are doing their data collection remotely.
Crystal dehydration
Beamlines have become highly automated with robotic systems that increase the speed and reliability of sample transfer yielding a much more efficient use of time by the researchers thus impacting on their success in achieving structural solution.
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 greater time and effort to obtain a positives outcome and some may benefit from specialised techniques to improve their diffraction properties.
Some of these techniques are applied prior to crystal growth and others once crystals are available. Post-crystallisation techniques take into consideration the dynamic nature of macromolecular crystals that are sometimes capable of short- and long-range rearrangements. This reorganization is often detrimental to the diffraction qualities of the crystal, but in certain cases can lead to greater internal order, lower solvent content or a change in space group that may result in improved diffraction or a higher quality data set. These techniques include soaking the crystal with different compounds, chemical cross-linking, crystal annealing and dehydration.
I am very interested in a number of these techniques that, despite having proven to be successful in numerous cases, are rarely used and are currently left for desperate cases. I would like to undertake controlled and systematic studies of their effects 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 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. They are an interesting group of proteins as they catalyse a series of reactions in bacteria of not very well understood relevance. There are even studies that suggest it may be have a metabolic significance in eukaryotes, making PQQ be a potential new vitamin, but results are somewhat contradictory at the moment. The other key interest of these proteins is that they are used as biosensors in medical applications thus understanding their biochemistry is of great interest.
My main research interest in this area has focused on understanding the structural determinants that modulate substrate selectivity in a particular Soluble Glucose Dehydrogenase from A. calcoaceticus. This enzyme is used in commercial blood glucose sensors and this 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.
Selected Publications
- 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)
- 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)
- 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.
- Crystallization of quinoprotein glucose dehydrogenase variants and homologues by microseeding J Sanchez-Weatherby, S Southall, A Oubrie, (2006). Acta Cryst F 62: 518-521.
- 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.