Holak T A, Borer P N, Levy G C, van Boom J H, Wang A H
Nucleic Acids Res. 1984 Jun 11;12(11):4625-35. doi: 10.1093/nar/12.11.4625.
In 4M NaCl solutions (dC-dG)n (n = 3,4; approximately 9 mM) exist as a mixture o +/- B and Z forms. The low and high field components of two 31P NMR resonances originating from internal phosphodiester groups are assigned to the GpC and CpG linkages, respectively. Low temperatures stabilize the Z-forms, which completely disappear above 50 degrees C (n = 3) and 65 degrees C (n = 4). delta H = -44 and -17 kJ/mol for B to Z transition in the hexamer and octamer duplexes, respectively. Temperature dependent changes (0-50 degrees C range) in the spin-lattice relaxation times at 145.7 MHz are distinctly different for the 31P nuclei o +/- GpC and CpG groups. The relaxation data can be explained by assuming that the GpC phosphodiester groups undergo more local internal motion than do the CpG groups.
在4M氯化钠溶液中，(dC-dG)n（n = 3,4；约9 mM）以α/β和Z型的混合物形式存在。源自内部磷酸二酯基团的两个31P NMR共振的低场和高场成分分别对应于GpC和CpG连接。低温会使Z型稳定，在50℃（n = 3）和65℃（n = 4）以上Z型会完全消失。六聚体和八聚体双链体中从B型到Z型转变的ΔH分别为-44和-17 kJ/mol。在145.7 MHz下，31P核的α/β GpC和CpG基团的自旋晶格弛豫时间随温度的变化（0-50℃范围）明显不同。弛豫数据可以通过假设GpC磷酸二酯基团比CpG基团经历更多的局部内部运动来解释。
