YC Plenary Sessions 1 & 2

By | April 18, 2011

The British Crystallography Association (BCA) kicked off last 11th April 2011 at Keele University with two YC sessions comprised of a plenary lecture followed by a series of 15-minute presentations of research projects of various YC members. The chairs for the first and second sessions were Duncan Sneddon (Diamond Light Source) and William Lewis (University of Nottingham) respectively.

Matthew Johnson (GSK) talked about the Industrial Group of BCA

The first plenary session was by Matthew Johnson from GlaxoSmithKline. He gave an overview of what Industrial Group do in terms of bridging the two seemingly separate yet interconnected world of academia and industry. He explained that in an ideal world, the great scientific ideas and concepts of the university is transferred to an innovative techniques and applications by the industry. The industry then creates the product, for instance, a pill or windshield that enters the market. The industry provides feedback to the university which generates new concept, then cycles back again to the industry. However, the real world is far from the ideal and therefore, the IG provides this bridge in the form of meetings, conferences and workshops that brings industry and academia to have discussion. On the second part of his session, he introduced what an industrial crystallographer. He presented brief introduction of a wide variety of research projects by an industrial crystallographers, which includes but not limited to understanding of minerals in glass coating and analysis of platinum concentration in road dust using X-ray fluorescence.

Arwen Pearson (University of Leeds) talked about complementary methods of X-ray crystallography

The second plenary session was by the chair of the BCA Spring Meeting 2011 programme committee, Arwen Pearson from University of Leeds. She talked about complementary methods to give more structural information from a single crystal. As a structural biologist, the reason why we want to find out how the structure looks like is because we want to know how different life processes works. And in many occasions, we find ourselves looking at static structures because of the nature of the crystallization. However, it is crucial for us to explore the intermediate states to better understand the processes. For instance, we want to see how a protein structure changes over time. To do this, we can exploit the protein crystal packing. Proteins packed in such a way that it gives a few gaps in between of which the substrate can get incorporated into and many times proteins retain their catalytic activity even in a crystalline state. As such this allows visualisation of the intermediate reaction. There are two ways to do this. One is through time-resolved Laue diffraction data collection, which will provide a real time view. However, this is not used as often because of its requirement of reversibility. The other method is though rapid cryotrapping technique to arrest the reaction at a spectroscopically defined intermediate for X-ray structure determination. This method, however, poses a problem on the electron density map as it gives ambiguous answer for isosteric structures that look similar but electronically and chemically distinct. To deal with this problem, complementary spectroscopy approach can be used. She focused on two approaches – using UV-Vis fluorescence and Raman spectroscopy. A specialized portable microspectrophotometer for this method can be found in www.4DX.se. It is highly important to take note that the kinetics in the crystal is not always the same as the enzyme kinetics in solution. Proteins in crystal form often in extreme pH, have higher ionic strength, and viscosity media; this of which change the rate of reaction and can create off pathway intermediates. Another technique (flow cell) can be used to get around with this problem. She then presented some case studies that exploit these complementary methods – redox reaction of methylamine dehydrogenase and reaction intermediates in the O2 activation mechanism of of 2,3-homoprotocatechuate dioxygenase. She ended her session by reminding everyone that single crystal spectroscopy should be done as a matter of routine for any mechanistic crystallographic project. This is to prevent artificial structural information caused by radiation damage from X-ray. Majority of the synchrotron facilities such as ESRF, Swiss Light Source and NSLS provide such service.

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