Faster route to NMR chemical shift data

A new technique makes it easier and faster to determine a type of fundamental nuclear magnetic resonance spectroscopy value that is rich with information about molecules. Known as chemical shift anisotropy (CSA) tensors, these values previously have been difficult to obtain. CSA tensors measure variations in NMR chemical shifts that occur when a functional group in a protein or other compound changes orientation with respect to a fixed magnetic field. Chemists use CSA data to refine protein structures, elucidate enzyme mechanisms, and validate theoretical calculations of atomic properties. Traditionally, researchers could measure only one CSA tensor at a time, and recent advanced techniques boosted this to about 10 tensors per experiment. Now, Chad M. Rienstra and coworkers at the University of Illinois, Urbana-Champaign, have devised a way to obtain about 100 CSA tensors at a time (J. Am. Chem. Soc. 2007, 129, 5318). They report using the technique to determine about 95% of the CSA tensors in a small protein and have since achieved similar results with larger proteins.