Upgrade to 600 MHz NMR spectrometer

点击翻译按钮获取中文摘要

Nuclear Magnetic Resonance (NMR) is a spectroscopic technique closely related to Magnetic Resonance Imaging (MRI). It is a very versatile technique. Its biggest application lies in its ability to provide detailed information on interactions between molecules. Proteins up to about 30 kDa (250 amino acid residues) can have backbone signals assigned rapidly and almost automatically. This means that we can rapidly and simply work out which signal comes from which amino acid, thereby providing a fingerprint of the protein. Addition of a ligand (for example a small molecule drug, or another protein) produces changes in signals, which are straightforwardly analysed to determine where the ligand is binding, and often to produce a binding affinity. With larger proteins, similar information can be obtained in slightly different ways although with rather more experimental effort. Very large proteins (including membrane proteins and receptors in intact cells) are still amenable to investigation, and there are straightforward techniques for identifying which ligands bind to such targets, and which parts of the ligands are most closely in contact. NMR has many other uses. It can be used to calculate the structures of proteins in solution, to analyse local and global mobility, to look at structural change on alteration of solution conditions or addition of ligands, to measure local pKa values of charged sidechains, to analyse the metabolites present in complex mixtures such as body fluids, to follow metabolic and enzymatic processes, and much more. Extracting such information is not always straightforward and often requires expert advice and intervention.Currently we carry out many such analyses on a range of targets, often as a result of problems being investigated by external users that we are asked to advise on. Selection of projects is made on the basis of scientific importance rather than funding, although funding is clearly of considerable importance. Our current equipment is old and becoming obsolete, and is therefore likely to fail catastrophically at some point over the next few years. We are looking to replace it with new equipment, which has very similar capabilities, although the intervening years have led to improvements in many systems, for example more stable electronics and more rapid switching. The upgraded instrument will therefore be able to do the same things as our current instrument, but better and faster, with fewer instrumental artifacts and limitations. It will have some new capabilities, which will enable us to carry out a wider range of investigations, and will bring it up to the highest international standards. The current instrument has lasted 18 years: we expect the upgraded instrument to last at least another 10 and hopefully considerably longer. The funding required is thus a very cost-effective solution to the provision of world-class NMR facilities. The upgraded instrument will be used for a wide range of projects, with users mainly from Sheffield but also further afield. These include investigation of amyloid proteins (the cause of Alzheimer's disease); fundamental research on protein stability and solubility in solution; work on the mechanism of kinases and phosphoryl transferases (key regulatory enzymes within metabolic pathways; investigations on bacterial proteins that recognise specific parts of bacterial cell walls and could therefore be used as a basis for both antibiotics and novel diagnostic tools; investigations of the function of specific proteins; and the development of high-pressure NMR as a tool for investigating the relatively low-population active forms of proteins. The instrument therefore provides an important resource for many problems in biomolecular research.