Zhang S, Gorenstein D G
Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston 77555-1157, USA.
J Magn Reson. 1998 May;132(1):81-7. doi: 10.1006/jmre.1998.1388.
A Gaussian-shaped, offset-independent adiabatic decoupling is adopted to decouple 13CO from 13C alpha or vice versa for 13C- and 15N-double-labeled proteins, together with a compensating decoupling applied on the opposite side of the 13C alpha resonance frequency. In a quite broad range, the double-adiabatic decoupling eliminates efficiently the cyclic sidebands caused by direct irradiation of the adiabatic decoupling and reduces significantly the Bloch-Siegert shift. The remaining Bloch-Siegert shift, which is almost a linear function of offset, can be removed by a dilated evolution time. The decoupling sequence is also quite insensitive to the RF field intensity or inhomogeneity due to the reduced transverse components of RF field at 13C alpha, leading to an efficient decoupling even under unfavorable conditions.
对于13C和15N双标记的蛋白质，采用高斯形状、与偏移无关的绝热去耦来使13CO与13Cα去耦，反之亦然，同时在13Cα共振频率的另一侧施加补偿去耦。在相当宽的范围内，双绝热去耦有效地消除了由绝热去耦直接照射引起的循环边带，并显著降低了布洛赫-西格特位移。剩余的布洛赫-西格特位移几乎是偏移的线性函数，可以通过延长演化时间来消除。由于13Cα处射频场的横向分量减小，去耦序列对射频场强度或不均匀性也相当不敏感，即使在不利条件下也能实现高效去耦。
