Modified Triple Resonance NMR Experiments with Optimized Sensitivity for Rapidly Exchanging Protons

摘要

Multidimensional NMR spectroscopy has developed into the premier method for determining high-resolution structures of molecules in solution. A major concern in the development of pulse sequences is improving the sensitivity of the NMR experiments. Theweakest signals in NMR spectra often arise from amide protons that exchange rapidly with the solvent water, and these weak signals often constitute the limiting factor in signal assignment and structure determination of proteins. The intensity of theseresonances can be enhanced when the water signal is not saturated during the pulse sequence. We describe here modified triple resonance experiments in which the water signal is not saturated and composite pulse proton decoupling is used. The modified pulse sequences yield a sensitivity gain of up to 50% for rapidly exchanging amide protons, where enhanced sensitivity is of outstanding importance.