NMR structural studies of glutathione S-transferase.

The use of nuclear magnetic resonance (NMR) spectroscopy for the structure determination of small proteins is now widely recognized; what is less frequently reported is the application of NMR techniques for high-resolution studies of large proteins (M(r) larger than 30 kD). We demonstrate here how an integrated approach, using heteronuclear NMR and X-ray crystallography, can provide useful and biologically important information for large protein systems. The dynamic features of the human Al-1 glutathione S-transferase and the role of the C-terminal region are being probed by NMR; in the X-ray crystal structure, the electron densities for this region of the protein are uninterpretable.