Brandes R, Vold R R, Vold R L, Kearns D R
Biochemistry. 1986 Nov 18;25(23):7744-51. doi: 10.1021/bi00371a069.
Deuterium quadrupole echo spectra and spin-lattice relaxation rates measured at 76.8 and 38.4 MHz as a function of relative humidity are reported for calf thymus DNA deuterated at positions A8 and G8. The amplitude of base pair motion is observed to increase slightly with increasing degree of hydration (up to approximately 20 mol of H2O/nucleotide), and the onset of motion is associated with a more than 100-fold drop in T1. This observed decrease in T1 parallels that observed previously for the phosphate backbone and appears to be characteristic of collective modes of motion. Above approximately 20 mol of H2O/nucleotide, the amplitude of the base motion increases substantially up to a point where slow components of motion lead to a complete loss of the quadrupole echo.
报道了在76.8和38.4 MHz下测量的、作为相对湿度函数的、在A8和G8位置氘代的小牛胸腺DNA的氘四极回波光谱和自旋晶格弛豫率。观察到随着水合程度的增加（高达约20摩尔H₂O/核苷酸），碱基对运动的幅度略有增加，并且运动的开始与T1下降超过100倍相关。观察到的T1下降与先前在磷酸主链中观察到的下降相似，并且似乎是集体运动模式的特征。在约20摩尔H₂O/核苷酸以上，碱基运动的幅度大幅增加，直至运动的慢成分导致四极回波完全消失的点。
