Double-Nucleus Enhanced Recoupling for Efficient 13C MAS NMR Correlation Spectroscopy of Perdeuterated Proteins
Umit Akbey, Hartmut Oschkinat and Barth-Jan van Rossum*
The use of both proton and deuterium dipolar coupling networks to obtain efficient 13C magic-angle-spinning NMR correlation spectroscopy is introduced. This new strategy aims to improve the efficiency of 13C spin diffusion in perdeuterated proteins. The method is called double-nucleus enhanced recoupling (DONER), and it provides significantly improved transfer efficiency for carbon spin diffusion at low proton density. The Cα cross-peak intensity in the DONER experiment is 3 and 5 times stronger than those in conventional radio-frequency-assisted diffusion (RAD) and proton-driven spin diffusion (PDSD) experiments, respectively. Remarkably, the full cross-peak pattern for the aliphatic region of an extensively perdeuterated SH3 protein sample can be obtained using the DONER approach with direct 13C excitation.