Magnetic susceptibility

Click on picture to enlarge view

An ultra-highfield wide-bore NMR machine is now being prototyped at Leiden University. The machine will let scientists look closely at membrane proteins at resolutions higher than ever possible before.

The Bruker machine runs at 750 MHz radio frequency, which is a twofold increase on solid state NMR used for biochemical studies and marks a 60% increase in sensitivity. With its highly stable 17.6 T superconducting magnet having a wide bore large samples and even living creatures can now be studied. The machine exploits magic angle spinning (MAS) in which a sample is spun at 54.5 degrees to the main field leading to much sharper spectral peaks. Team leader Huub de Groot says this means membrane proteins can now be studied in situ. Early experiments have already allowed the researchers at Leiden to assign most of the carbon, nitrogen, and proton signals from a 63 residue protein in the solid state by separating some 350 signals.

There are some 50,000 membrane proteins in the human body but little is known about any of them. Many of them, however, represent potential targets for drug designers for diseases from arthritis to depression.