NMR detection of protein N-15 spins near paramagnetic lanthanide ions

作者：John Michael; Park Ah Young; Dixon Nicholas E; Otting Gottfried^*

来源：Journal of the American Chemical Society, 2007, 129(3): 462-463.

DOI：10.1021/ja066995o

Pronounced paramagnetic relaxation enhancement (PRE) due to paramagnetic metal ions prevents the observation of NMR signals from H-1 spins near the metal. While N-15 spins are less prone to PRE, the intrinsic sensitivity of N-15 NMR spectroscopy is low. This Communication presents a H-1 detected out-and-back N-z-exchange experiment which allows the measurement of pseudocontact shifts of N-15 spins located as close as 6 angstrom from a Dy3+ ion in a 30 kDa protein complex. The experiment relies on the chemical exchange between paramagnetic and diamagnetic metal ions during two mixing times during which the N-15 magnetization is stored as PRE-insensitive longitudinal magnetization. It is demonstrated with the complex between the subunit and the N-terminal domain of the subunit of E. coli DNA polymerase III, prepared with a mixture of Dy3+ and La3+. Pseudocontact shifts were measured for 61 N-15 spins which were not observable in a conventional N-15-HSQC spectrum.

• 出版日期2007-1-24